diff --git a/bot/bot.rkt b/bot/bot.rkt
index db10331..0c46330 100644
--- a/bot/bot.rkt
+++ b/bot/bot.rkt
@@ -19,25 +19,27 @@
 
           (define (bouncy-box)
             (define me (symbol->string (strong-gensym 'user)))
-            (define start-time (current-inexact-milliseconds))
-            (define-field deadline start-time)
-            (define-field x (* (- (random) 0.5) 100))
+
+            (define x (* (- (random) 0.5) 100))
             (define y0 (+ 1.0 (* (random) 10)))
-            (define-field y y0)
-            (define-field z (* (- (random) 0.5) 100))
-            (at ds
-              (on (asserted (LaterThan (deadline)))
-                (deadline (+ (deadline) (/ 1000 10)))
-                (y (+ y0 (cos (/ (- (deadline) start-time) 1000.0 (/ 1 2 pi)))))))
+            (define z (* (- (random) 0.5) 100))
             (define r (random))
             (define g (random))
             (define b (random))
+
+            (define-field y y0)
+            (define start-time (current-inexact-milliseconds))
+            (define-field deadline start-time)
+            (at ds
+              (on (asserted (LaterThan (deadline)))
+                (deadline (+ (deadline) (/ 1000 30)))
+                (y (+ y0 (cos (/ (- (deadline) start-time) 1000.0 (/ 1 2 pi)))))))
+
             (at scene
-              (assert (Sprite me (Move (Vector3 (x) (y) (z))
-                                       (Color-opaque r g b (Box)))))
-              ))
+                (assert (Variable me 'y (y)))
+                (assert (Sprite me '(y) (Move (ImmediateVector3 x 'y z) (Color-opaque r g b (Box)))))))
 
           (for [(i 100)] (bouncy-box)))))
 
-    (run-tcp-client-relay ds #:hostname "vr.demo.leastfixedpoint.com" #:port 9001
+    (run-tcp-client-relay ds #:hostname "localhost" #;"vr.demo.leastfixedpoint.com" #:port 9001
                           #:import (lambda (v) (on-connected (embedded-value v))))))
diff --git a/bot/schemas/scene.rkt b/bot/schemas/scene.rkt
index 0ef34da..711ccd2 100644
--- a/bot/schemas/scene.rkt
+++ b/bot/schemas/scene.rkt
@@ -59,7 +59,10 @@
      ((and dest
            (record
             'gravity
-            (list (app shapes:parse-Vector3 (and ?direction (not (== eof)))))))
+            (list
+             (app
+              shapes:parse-LiteralVector3
+              (and ?direction (not (== eof)))))))
       (Gravity ?direction))
      (_ eof)))
   (define parse-Gravity! (parse-success-or-error 'parse-Gravity parse-Gravity))
@@ -89,7 +92,9 @@
             (list
              (and ?name (? string?))
              (app parse-PortalDestination (and ?destination (not (== eof))))
-             (app shapes:parse-Vector3 (and ?position (not (== eof)))))))
+             (app
+              shapes:parse-LiteralVector3
+              (and ?position (not (== eof)))))))
       (Portal ?name ?destination ?position))
      (_ eof)))
   (define parse-Portal! (parse-success-or-error 'parse-Portal parse-Portal))
diff --git a/bot/schemas/shapes.rkt b/bot/schemas/shapes.rkt
index a1d87e4..d40e77f 100644
--- a/bot/schemas/shapes.rkt
+++ b/bot/schemas/shapes.rkt
@@ -172,21 +172,21 @@
            (record
             'scale
             (list
-             (app parse-Vector3 (and ?v (not (== eof))))
+             (app parse-LiteralVector3 (and ?v (not (== eof))))
              (app parse-CSGExpr (and ?shape (not (== eof)))))))
       (CSGExpr-scale ?v ?shape))
      ((and dest
            (record
             'move
             (list
-             (app parse-Vector3 (and ?v (not (== eof))))
+             (app parse-LiteralVector3 (and ?v (not (== eof))))
              (app parse-CSGExpr (and ?shape (not (== eof)))))))
       (CSGExpr-move ?v ?shape))
      ((and dest
            (record
             'rotate
             (list
-             (app parse-Vector3 (and ?v (not (== eof))))
+             (app parse-LiteralVector3 (and ?v (not (== eof))))
              (app parse-CSGExpr (and ?shape (not (== eof)))))))
       (CSGExpr-rotate ?v ?shape))
      ((and dest
@@ -235,9 +235,9 @@
         (record
          'color
          (list
-          (exact->inexact (*->preserve ?r))
-          (exact->inexact (*->preserve ?g))
-          (exact->inexact (*->preserve ?b))
+          (*->preserve ?r)
+          (*->preserve ?g)
+          (*->preserve ?b)
           (*->preserve ?shape))))))))
   (struct
    Color-transparent
@@ -253,10 +253,10 @@
         (record
          'color
          (list
-          (exact->inexact (*->preserve ?r))
-          (exact->inexact (*->preserve ?g))
-          (exact->inexact (*->preserve ?b))
-          (exact->inexact (*->preserve ?alpha))
+          (*->preserve ?r)
+          (*->preserve ?g)
+          (*->preserve ?b)
+          (*->preserve ?alpha)
           (*->preserve ?shape))))))))
   (define (parse-Color input)
     (match
@@ -265,23 +265,53 @@
            (record
             'color
             (list
-             (and ?r (? flonum?))
-             (and ?g (? flonum?))
-             (and ?b (? flonum?))
+             (app parse-DoubleValue (and ?r (not (== eof))))
+             (app parse-DoubleValue (and ?g (not (== eof))))
+             (app parse-DoubleValue (and ?b (not (== eof))))
              (app parse-Shape (and ?shape (not (== eof)))))))
       (Color-opaque ?r ?g ?b ?shape))
      ((and dest
            (record
             'color
             (list
-             (and ?r (? flonum?))
-             (and ?g (? flonum?))
-             (and ?b (? flonum?))
-             (and ?alpha (? flonum?))
+             (app parse-DoubleValue (and ?r (not (== eof))))
+             (app parse-DoubleValue (and ?g (not (== eof))))
+             (app parse-DoubleValue (and ?b (not (== eof))))
+             (app parse-DoubleValue (and ?alpha (not (== eof))))
              (app parse-Shape (and ?shape (not (== eof)))))))
       (Color-transparent ?r ?g ?b ?alpha ?shape))
      (_ eof)))
   (define parse-Color! (parse-success-or-error 'parse-Color parse-Color))
+  (define (DoubleValue? p)
+    (or (DoubleValue-immediate? p) (DoubleValue-reference? p)))
+  (struct
+   DoubleValue-immediate
+   (value)
+   #:transparent
+   #:methods
+   gen:preservable
+   ((define/generic *->preserve ->preserve)
+    (define (->preserve preservable)
+      (match
+       preservable
+       ((DoubleValue-immediate src) (exact->inexact (*->preserve src)))))))
+  (struct
+   DoubleValue-reference
+   (value)
+   #:transparent
+   #:methods
+   gen:preservable
+   ((define/generic *->preserve ->preserve)
+    (define (->preserve preservable)
+      (match preservable ((DoubleValue-reference src) (*->preserve src))))))
+  (define (parse-DoubleValue input)
+    (match
+     input
+     ((and dest (? flonum?)) (DoubleValue-immediate dest))
+     ((and dest (? symbol?)) (DoubleValue-reference dest))
+     (_ eof)))
+  (define parse-DoubleValue!
+    (parse-success-or-error 'parse-DoubleValue parse-DoubleValue))
   (struct
    External
    (path)
@@ -324,7 +354,19 @@
   (define parse-Floor! (parse-success-or-error 'parse-Floor parse-Floor))
   (struct
    Ground
-   (size)
+   ()
+   #:transparent
+   #:methods
+   gen:preservable
+   ((define/generic *->preserve ->preserve)
+    (define (->preserve preservable)
+      (match preservable ((Ground) (record 'ground (list)))))))
+  (define (parse-Ground input)
+    (match input ((and dest (record 'ground (list))) (Ground)) (_ eof)))
+  (define parse-Ground! (parse-success-or-error 'parse-Ground parse-Ground))
+  (struct
+   ImmediateQuaternion
+   (a b c d)
    #:transparent
    #:methods
    gen:preservable
@@ -332,17 +374,84 @@
     (define (->preserve preservable)
       (match
        preservable
-       ((Ground ?size) (record 'ground (list (*->preserve ?size))))))))
-  (define (parse-Ground input)
+       ((ImmediateQuaternion ?a ?b ?c ?d)
+        (record
+         'q
+         (list
+          (*->preserve ?a)
+          (*->preserve ?b)
+          (*->preserve ?c)
+          (*->preserve ?d))))))))
+  (define (parse-ImmediateQuaternion input)
     (match
      input
      ((and dest
            (record
-            'ground
-            (list (app parse-Vector2 (and ?size (not (== eof)))))))
-      (Ground ?size))
+            'q
+            (list
+             (app parse-DoubleValue (and ?a (not (== eof))))
+             (app parse-DoubleValue (and ?b (not (== eof))))
+             (app parse-DoubleValue (and ?c (not (== eof))))
+             (app parse-DoubleValue (and ?d (not (== eof)))))))
+      (ImmediateQuaternion ?a ?b ?c ?d))
      (_ eof)))
-  (define parse-Ground! (parse-success-or-error 'parse-Ground parse-Ground))
+  (define parse-ImmediateQuaternion!
+    (parse-success-or-error
+     'parse-ImmediateQuaternion
+     parse-ImmediateQuaternion))
+  (struct
+   ImmediateVector2
+   (x y)
+   #:transparent
+   #:methods
+   gen:preservable
+   ((define/generic *->preserve ->preserve)
+    (define (->preserve preservable)
+      (match
+       preservable
+       ((ImmediateVector2 ?x ?y)
+        (record 'v (list (*->preserve ?x) (*->preserve ?y))))))))
+  (define (parse-ImmediateVector2 input)
+    (match
+     input
+     ((and dest
+           (record
+            'v
+            (list
+             (app parse-DoubleValue (and ?x (not (== eof))))
+             (app parse-DoubleValue (and ?y (not (== eof)))))))
+      (ImmediateVector2 ?x ?y))
+     (_ eof)))
+  (define parse-ImmediateVector2!
+    (parse-success-or-error 'parse-ImmediateVector2 parse-ImmediateVector2))
+  (struct
+   ImmediateVector3
+   (x y z)
+   #:transparent
+   #:methods
+   gen:preservable
+   ((define/generic *->preserve ->preserve)
+    (define (->preserve preservable)
+      (match
+       preservable
+       ((ImmediateVector3 ?x ?y ?z)
+        (record
+         'v
+         (list (*->preserve ?x) (*->preserve ?y) (*->preserve ?z))))))))
+  (define (parse-ImmediateVector3 input)
+    (match
+     input
+     ((and dest
+           (record
+            'v
+            (list
+             (app parse-DoubleValue (and ?x (not (== eof))))
+             (app parse-DoubleValue (and ?y (not (== eof))))
+             (app parse-DoubleValue (and ?z (not (== eof)))))))
+      (ImmediateVector3 ?x ?y ?z))
+     (_ eof)))
+  (define parse-ImmediateVector3!
+    (parse-success-or-error 'parse-ImmediateVector3 parse-ImmediateVector3))
   (struct
    Light
    (v)
@@ -364,6 +473,37 @@
       (Light ?v))
      (_ eof)))
   (define parse-Light! (parse-success-or-error 'parse-Light parse-Light))
+  (struct
+   LiteralVector3
+   (x y z)
+   #:transparent
+   #:methods
+   gen:preservable
+   ((define/generic *->preserve ->preserve)
+    (define (->preserve preservable)
+      (match
+       preservable
+       ((LiteralVector3 ?x ?y ?z)
+        (record
+         'v
+         (list
+          (exact->inexact (*->preserve ?x))
+          (exact->inexact (*->preserve ?y))
+          (exact->inexact (*->preserve ?z)))))))))
+  (define (parse-LiteralVector3 input)
+    (match
+     input
+     ((and dest
+           (record
+            'v
+            (list
+             (and ?x (? flonum?))
+             (and ?y (? flonum?))
+             (and ?z (? flonum?)))))
+      (LiteralVector3 ?x ?y ?z))
+     (_ eof)))
+  (define parse-LiteralVector3!
+    (parse-success-or-error 'parse-LiteralVector3 parse-LiteralVector3))
   (define (Mesh? p)
     (or (Mesh-Sphere? p)
         (Mesh-Box? p)
@@ -508,36 +648,32 @@
   (define (parse-Plane input)
     (match input ((and dest (record 'plane (list))) (Plane)) (_ eof)))
   (define parse-Plane! (parse-success-or-error 'parse-Plane parse-Plane))
+  (define (Quaternion? p)
+    (or (Quaternion-immediate? p) (Quaternion-reference? p)))
   (struct
-   Quaternion
-   (a b c d)
+   Quaternion-immediate
+   (value)
    #:transparent
    #:methods
    gen:preservable
    ((define/generic *->preserve ->preserve)
     (define (->preserve preservable)
-      (match
-       preservable
-       ((Quaternion ?a ?b ?c ?d)
-        (record
-         'q
-         (list
-          (exact->inexact (*->preserve ?a))
-          (exact->inexact (*->preserve ?b))
-          (exact->inexact (*->preserve ?c))
-          (exact->inexact (*->preserve ?d)))))))))
+      (match preservable ((Quaternion-immediate src) (*->preserve src))))))
+  (struct
+   Quaternion-reference
+   (value)
+   #:transparent
+   #:methods
+   gen:preservable
+   ((define/generic *->preserve ->preserve)
+    (define (->preserve preservable)
+      (match preservable ((Quaternion-reference src) (*->preserve src))))))
   (define (parse-Quaternion input)
     (match
      input
-     ((and dest
-           (record
-            'q
-            (list
-             (and ?a (? flonum?))
-             (and ?b (? flonum?))
-             (and ?c (? flonum?))
-             (and ?d (? flonum?)))))
-      (Quaternion ?a ?b ?c ?d))
+     ((app parse-ImmediateQuaternion (and dest (not (== eof))))
+      (Quaternion-immediate dest))
+     ((and dest (? symbol?)) (Quaternion-reference dest))
      (_ eof)))
   (define parse-Quaternion!
     (parse-success-or-error 'parse-Quaternion parse-Quaternion))
@@ -873,7 +1009,7 @@
   (define parse-Sphere! (parse-success-or-error 'parse-Sphere parse-Sphere))
   (struct
    Sprite
-   (name shape)
+   (name formals shape)
    #:transparent
    #:methods
    gen:preservable
@@ -881,8 +1017,13 @@
     (define (->preserve preservable)
       (match
        preservable
-       ((Sprite ?name ?shape)
-        (record 'sprite (list (*->preserve ?name) (*->preserve ?shape))))))))
+       ((Sprite ?name ?formals ?shape)
+        (record
+         'sprite
+         (list
+          (*->preserve ?name)
+          (for/list ((item (in-list ?formals))) (*->preserve item))
+          (*->preserve ?shape))))))))
   (define (parse-Sprite input)
     (match
      input
@@ -891,8 +1032,9 @@
             'sprite
             (list
              (and ?name (? string?))
+             (list (and ?formals (? symbol?)) ...)
              (app parse-Shape (and ?shape (not (== eof)))))))
-      (Sprite ?name ?shape))
+      (Sprite ?name ?formals ?shape))
      (_ eof)))
   (define parse-Sprite! (parse-success-or-error 'parse-Sprite parse-Sprite))
   (struct
@@ -962,7 +1104,7 @@
          (*->preserve ?path)
          (*->preserve ?scale)
          (*->preserve ?offset)
-         (exact->inexact (*->preserve ?alpha))))))))
+         (*->preserve ?alpha)))))))
   (define (parse-TextureSpec input)
     (match
      input
@@ -978,7 +1120,7 @@
             (and ?path (? string?))
             (app parse-Vector2 (and ?scale (not (== eof))))
             (app parse-Vector2 (and ?offset (not (== eof))))
-            (and ?alpha (? flonum?))))
+            (app parse-DoubleValue (and ?alpha (not (== eof))))))
       (TextureSpec-uvAlpha ?path ?scale ?offset ?alpha))
      (_ eof)))
   (define parse-TextureSpec!
@@ -1006,8 +1148,8 @@
   (define parse-Touchable!
     (parse-success-or-error 'parse-Touchable parse-Touchable))
   (struct
-   Vector2
-   (x y)
+   Variable
+   (spriteName variable value)
    #:transparent
    #:methods
    gen:preservable
@@ -1015,47 +1157,79 @@
     (define (->preserve preservable)
       (match
        preservable
-       ((Vector2 ?x ?y)
+       ((Variable ?spriteName ?variable ?value)
         (record
-         'v
+         'variable
          (list
-          (exact->inexact (*->preserve ?x))
-          (exact->inexact (*->preserve ?y)))))))))
-  (define (parse-Vector2 input)
-    (match
-     input
-     ((and dest (record 'v (list (and ?x (? flonum?)) (and ?y (? flonum?)))))
-      (Vector2 ?x ?y))
-     (_ eof)))
-  (define parse-Vector2! (parse-success-or-error 'parse-Vector2 parse-Vector2))
-  (struct
-   Vector3
-   (x y z)
-   #:transparent
-   #:methods
-   gen:preservable
-   ((define/generic *->preserve ->preserve)
-    (define (->preserve preservable)
-      (match
-       preservable
-       ((Vector3 ?x ?y ?z)
-        (record
-         'v
-         (list
-          (exact->inexact (*->preserve ?x))
-          (exact->inexact (*->preserve ?y))
-          (exact->inexact (*->preserve ?z)))))))))
-  (define (parse-Vector3 input)
+          (*->preserve ?spriteName)
+          (*->preserve ?variable)
+          (*->preserve ?value))))))))
+  (define (parse-Variable input)
     (match
      input
      ((and dest
            (record
-            'v
+            'variable
             (list
-             (and ?x (? flonum?))
-             (and ?y (? flonum?))
-             (and ?z (? flonum?)))))
-      (Vector3 ?x ?y ?z))
+             (and ?spriteName (? string?))
+             (and ?variable (? symbol?))
+             ?value)))
+      (Variable ?spriteName ?variable ?value))
+     (_ eof)))
+  (define parse-Variable!
+    (parse-success-or-error 'parse-Variable parse-Variable))
+  (define (Vector2? p) (or (Vector2-immediate? p) (Vector2-reference? p)))
+  (struct
+   Vector2-immediate
+   (value)
+   #:transparent
+   #:methods
+   gen:preservable
+   ((define/generic *->preserve ->preserve)
+    (define (->preserve preservable)
+      (match preservable ((Vector2-immediate src) (*->preserve src))))))
+  (struct
+   Vector2-reference
+   (value)
+   #:transparent
+   #:methods
+   gen:preservable
+   ((define/generic *->preserve ->preserve)
+    (define (->preserve preservable)
+      (match preservable ((Vector2-reference src) (*->preserve src))))))
+  (define (parse-Vector2 input)
+    (match
+     input
+     ((app parse-ImmediateVector2 (and dest (not (== eof))))
+      (Vector2-immediate dest))
+     ((and dest (? symbol?)) (Vector2-reference dest))
+     (_ eof)))
+  (define parse-Vector2! (parse-success-or-error 'parse-Vector2 parse-Vector2))
+  (define (Vector3? p) (or (Vector3-immediate? p) (Vector3-reference? p)))
+  (struct
+   Vector3-immediate
+   (value)
+   #:transparent
+   #:methods
+   gen:preservable
+   ((define/generic *->preserve ->preserve)
+    (define (->preserve preservable)
+      (match preservable ((Vector3-immediate src) (*->preserve src))))))
+  (struct
+   Vector3-reference
+   (value)
+   #:transparent
+   #:methods
+   gen:preservable
+   ((define/generic *->preserve ->preserve)
+    (define (->preserve preservable)
+      (match preservable ((Vector3-reference src) (*->preserve src))))))
+  (define (parse-Vector3 input)
+    (match
+     input
+     ((app parse-ImmediateVector3 (and dest (not (== eof))))
+      (Vector3-immediate dest))
+     ((and dest (? symbol?)) (Vector3-reference dest))
      (_ eof)))
   (define parse-Vector3!
     (parse-success-or-error 'parse-Vector3 parse-Vector3)))
diff --git a/protocols/schemas/scene.prs b/protocols/schemas/scene.prs
index 320fe1a..4c882ca 100644
--- a/protocols/schemas/scene.prs
+++ b/protocols/schemas/scene.prs
@@ -1,12 +1,12 @@
 version 1 .
 
-Portal = <portal @name string @destination PortalDestination @position shapes.Vector3> .
+Portal = <portal @name string @destination PortalDestination @position shapes.LiteralVector3> .
 PortalDestination =
 / @local #!any
 / @remote noise.Route
 .
 
-Gravity = <gravity @direction shapes.Vector3> .
+Gravity = <gravity @direction shapes.LiteralVector3> .
 
 AmbientSound = <ambient-sound @name string @spec shapes.SoundSpec> .
 
diff --git a/protocols/schemas/shapes.prs b/protocols/schemas/shapes.prs
index 6de3322..9295e94 100644
--- a/protocols/schemas/shapes.prs
+++ b/protocols/schemas/shapes.prs
@@ -1,6 +1,7 @@
 version 1 .
 
-Sprite = <sprite @name string @shape Shape> .
+Sprite = <sprite @name string @formals [symbol ...] @shape Shape> .
+Variable = <variable @spriteName string @variable symbol @value any> .
 
 Shape = Mesh / Light / Scale / Move / Rotate / @many [Shape ...] / Texture / Color / Sound / Name / Floor / Nonphysical / Touchable / CSG / Skybox .
 
@@ -8,15 +9,23 @@ Mesh = Sphere / Box / Ground / Plane / External .
 
 Sphere = <sphere> .
 Box = <box> .
-Ground = <ground @size Vector2> .
+Ground = <ground> .
 Plane = <plane> .
 External = <external @path string> .
 
 Light = <hemispheric-light @v Vector3> .
 
-Vector2 = <v @x double @y double> .
-Vector3 = <v @x double @y double @z double> .
-Quaternion = <q @a double @b double @c double @d double> .
+DoubleValue = @immediate double / @reference symbol .
+
+ImmediateVector2 = <v @x DoubleValue @y DoubleValue> .
+ImmediateVector3 = <v @x DoubleValue @y DoubleValue @z DoubleValue> .
+ImmediateQuaternion = <q @a DoubleValue @b DoubleValue @c DoubleValue @d DoubleValue> .
+
+LiteralVector3 = <v @x double @y double @z double> .
+
+Vector2 = @immediate ImmediateVector2 / @reference symbol .
+Vector3 = @immediate ImmediateVector3 / @reference symbol .
+Quaternion = @immediate ImmediateQuaternion / @reference symbol .
 
 Scale = <scale @v Vector3 @shape Shape> .
 Move = <move @v Vector3 @shape Shape> .
@@ -26,12 +35,12 @@ Texture = <texture @spec TextureSpec @shape Shape> .
 TextureSpec =
 / @simple [@path string]
 / @uv [@path string @scale Vector2 @offset Vector2]
-/ @uvAlpha [@path string @scale Vector2 @offset Vector2 @alpha double]
+/ @uvAlpha [@path string @scale Vector2 @offset Vector2 @alpha DoubleValue]
 .
 
 Color =
-/ @opaque <color @r double @g double @b double @shape Shape>
-/ @transparent <color @r double @g double @b double @alpha double @shape Shape>
+/ @opaque <color @r DoubleValue @g DoubleValue @b DoubleValue @shape Shape>
+/ @transparent <color @r DoubleValue @g DoubleValue @b DoubleValue @alpha DoubleValue @shape Shape>
 .
 
 Sound = <sound @spec SoundSpec @shape Shape> .
@@ -50,9 +59,9 @@ CSG = <csg @expr CSGExpr> .
 
 CSGExpr =
 / <mesh @shape Mesh>
-/ <scale @v Vector3 @shape CSGExpr>
-/ <move @v Vector3 @shape CSGExpr>
-/ <rotate @v Vector3 @shape CSGExpr>
+/ <scale @v LiteralVector3 @shape CSGExpr>
+/ <move @v LiteralVector3 @shape CSGExpr>
+/ <rotate @v LiteralVector3 @shape CSGExpr>
 / <subtract [@base CSGExpr @more CSGExpr ...]>
 / <union [@base CSGExpr @more CSGExpr ...]>
 / <intersect [@base CSGExpr @more CSGExpr ...]>
diff --git a/scene/lobby.pr b/scene/lobby.pr
index 5e1f648..cb1abd9 100644
--- a/scene/lobby.pr
+++ b/scene/lobby.pr
@@ -1,14 +1,14 @@
-<sprite "light" <hemispheric-light <v 0.1 1.0 0.0>>>
+<sprite "light" [] <hemispheric-light <v 0.1 1.0 0.0>>>
 <gravity <v 0.0 -9.81 0.0>>
-<sprite "sky" <skybox "textures/Daylight Box UV_0">>
+<sprite "sky" [] <skybox "textures/Daylight Box UV_0">>
 
-<sprite "ground"
+<sprite "ground" []
  <texture ["textures/grass-256x256.jpg"
            <v 100.0 100.0>
            <v 0.0 0.0>]
-  <floor <ground <v 300.0 300.0>>>>>
+  <floor <scale <v 300.0 1.0 300.0> <ground>>>>>
 
-<sprite "box"
+<sprite "box" []
  <move <v -6.0 1.0 8.0>
   <scale <v 10.0 0.1 10.0>
    <texture ["textures/oak-herringbone-5e80fb40b00c9-1200.jpg"
@@ -17,20 +17,20 @@
              0.75]
     <floor <box>>>>>>
 
-<sprite "box2"
+<sprite "box2" []
  <move <v -500.0 0.5 3.0>
   <floor
    <color 0.0 0.0 1.0 1.0
     <scale <v 1000.0 1.0 1.0> <box>>>>>>
 
 <Exit "p" "lobby">
-<sprite "p"
+<sprite "p" []
  <move <v -999.5 2.0 3.0>
   <rotate <v 0.0 -0.25 0.0>
    <color 1.0 0.0 1.0
     <touchable <scale <v 1.0 2.0 1.0> <plane>>>>>>>
 
-<sprite "steps"
+<sprite "steps" []
  <color 0.0 0.5 0.0
   <move <v 0.0 0.0 3.5>
    <scale <v 1.0 1.0 3.0>
@@ -42,8 +42,9 @@
      ]>>>>>
 
 <Exit "door" "other">
-<sprite "door"
- <move <v -3.0 0.0 1.5>
+<variable "door" y 0.0>
+<sprite "door" [y]
+ <move <v -3.0 y 1.5>
   <rotate <v 0.0 -0.1 0.0> [
     <scale <v 1.0 2.11 1.0>
      <texture ["textures/door1.jpg"]
@@ -52,7 +53,7 @@
   ]>>>
 
 <portal "door2" <route [<ws "wss://vr.demo.eighty-twenty.org/ws">]>>
-<sprite "door2"
+<sprite "door2" []
  <move <v -5.0 0.0 1.5>
   <rotate <v 0.0 -0.1 0.0> [
     <scale <v 1.0 2.11 1.0>
@@ -61,14 +62,14 @@
     <scale <v 1.0 2.11 0.1> <move <v 0.0 0.5 0.6> <box>>>
   ]>>>
 
-<sprite "plans"
+<sprite "plans" []
  <texture ["plans/signal-2022-12-27-125451_002.jpeg"]
   <move <v 0.0 1.0 -10.0>
    <rotate <v 0.1 0.0 0.0>
     <scale <v 2.0 2.0 0.1>
      <box>>>>>>
 
-<sprite "tower"
+<sprite "tower" []
  <rotate <v 0.1 0.0 0.0>
   <move <v -10.0 50.0 13.0>
    <scale <v 3.0 100.0 3.0>
@@ -76,7 +77,7 @@
      <color 0.5 0.5 0.0
       <box>>>>>>>
 
-; <sprite "sponge"
+; <sprite "sponge" []
 ;  <move <v 4.0 1.6 0.0> [
 ;    <scale <v 0.001 0.001 0.001>
 ;     <external "objects/usnm_346-100k-obj/usnm_346-01-100k.obj">>
@@ -86,12 +87,12 @@
 ;       <box>>>>
 ;  ]>>
 
-; <sprite "sofa"
+; <sprite "sofa" []
 ;  <rotate <v -0.125 0.5 0.0>
 ;   <scale <v 0.01 0.01 0.01>
 ;    <external "objects/IKE020001_obj/IKEA-Arild_2_Seat_Sofa-3D.obj">>>>
 
-<sprite "x"
+<sprite "x" []
  <move <v 10.0 1.6 -5.0>
   <texture ["textures/oak-herringbone-5e80fb40b00c9-1200.jpg"
             <v 1.0 3.0 1.0>
@@ -105,7 +106,7 @@
     >>>>>
 
 ; <Exit "y" "lobby">
-; <sprite "y"
+; <sprite "y" []
 ;  <move <v 12.0 0.75 -5.0>
 ;   <texture ["textures/oak-herringbone-5e80fb40b00c9-1200.jpg"
 ;             <v 1.0 1.0 1.0>
diff --git a/scene/other.pr b/scene/other.pr
index a00947f..dab2cae 100644
--- a/scene/other.pr
+++ b/scene/other.pr
@@ -1,6 +1,6 @@
-<sprite "light" <hemispheric-light <v 0.1 1.0 0.0>>>
+<sprite "light" [] <hemispheric-light <v 0.1 1.0 0.0>>>
 ;<gravity <v 0.0 -9.81 0.0>>
-<sprite "sky" <skybox "textures/eso0932a">>
+<sprite "sky" [] <skybox "textures/eso0932a">>
 
 <ambient-sound "space" <loop "sounds/Space-atmosphere-sound/Space-atmosphere-sound.mp3">>
 
@@ -11,7 +11,7 @@
 ;   <floor <ground <v 300.0 300.0>>>>>
 
 <Exit "home" "lobby" <v -2.5 0.0 0.5>>
-<sprite "home"
+<sprite "home" []
  <move <v 0.0 0.0 -2.0>
   <rotate <v 0.0 -0.5 0.0> [
     <scale <v 1.0 2.11 1.0>
@@ -20,7 +20,7 @@
     <scale <v 1.0 2.11 0.1> <move <v 0.0 0.5 0.6> <box>>>
   ]>>>
 
-<sprite "x"
+<sprite "x" []
  <move <v 0.0 0.0 10.0>
   <texture ["textures/oak-herringbone-5e80fb40b00c9-1200.jpg"
             <v 1.0 3.0 1.0>
diff --git a/src/index.ts b/src/index.ts
index b479d10..1725b99 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,4 +1,4 @@
-import { is, fromJS, Dataflow, Dataspace, Embedded, Reader, Ref, Schemas, Sturdy, Turn } from "@syndicate-lang/core";
+import { is, fromJS, Dataflow, Dataspace, Embedded, Ref, Schemas, Turn } from "@syndicate-lang/core";
 import * as html from "@syndicate-lang/html";
 import * as timer from "@syndicate-lang/timer";
 import * as wsRelay from "@syndicate-lang/ws-relay";
@@ -14,7 +14,7 @@ import {
     Vector3,
 } from '@babylonjs/core/Legacy/legacy';
 
-import { activeFloorMeshes, activeTouchableMeshes, ShapeTree, v3, scale3, buildSound, builder as B } from './shapes.js';
+import { activeFloorMeshes, activeTouchableMeshes, Environment, ShapeTree, buildSound, builder as B, u2, u3, u3v } from './shapes.js';
 import { RunningEngine } from './engine.js';
 import { uuid } from './uuid.js';
 
@@ -22,13 +22,14 @@ assertion type SceneHandle(ds: Embedded<Ref>);
 
 function interpretScene(myId: string, runningEngine: RunningEngine, rootMesh: Mesh, sceneDs: Ref) {
     at sceneDs {
-        during Shapes.Sprite({ "name": $name: string }) => spawn named `sprite:${name}` {
+        during Shapes.Sprite({ "name": $name: string, "formals": $formals }) => spawn named `sprite:${name}` {
             if (name === myId) {
                 console.log('ignoring sprite', name);
             } else {
                 console.log('+shape', name);
                 on stop console.log('-shape', name);
-                spriteMain(name, runningEngine, rootMesh, sceneDs);
+                const env = new Environment(name, formals as symbol[], sceneDs);
+                spriteMain(env, runningEngine, rootMesh);
             }
         }
 
@@ -42,20 +43,20 @@ function interpretScene(myId: string, runningEngine: RunningEngine, rootMesh: Me
     }
 }
 
-function spriteMain(spriteName: string, runningEngine: RunningEngine, rootMesh: Mesh, sceneDs: Ref) {
-    at sceneDs {
-        let currentShape = ShapeTree.empty(spriteName, runningEngine.scene);
+function spriteMain(env: Environment, runningEngine: RunningEngine, rootMesh: Mesh) {
+    at env.sceneDs {
+        let currentShape = ShapeTree.empty(env.spriteName, runningEngine.scene);
         currentShape.rootnode.parent = rootMesh;
         on stop currentShape.remove();
-        during Shapes.Sprite({ "name": spriteName, "shape": $shape: Shapes.Shape }) => {
-            currentShape = currentShape.reconcile(spriteName, spriteName, shape);
+        during Shapes.Sprite({ "name": env.spriteName, "shape": $shape: Shapes.Shape }) => {
+            currentShape = currentShape.reconcile(env, env.spriteName, shape);
             currentShape.rootnode.parent = rootMesh;
         }
 
-        during SceneProtocol.Gravity($direction: Shapes.Vector3) => {
+        during SceneProtocol.Gravity($direction: Shapes.LiteralVector3) => {
             runningEngine.applyGravity = true;
             on stop runningEngine.applyGravity = false;
-            runningEngine.gravity = v3(direction);
+            runningEngine.gravity = new Vector3(direction.x, direction.y, direction.z);
         }
     }
 }
@@ -101,21 +102,23 @@ async function enterScene(
         }
     };
 
-    const currentPosition = () => Shapes.Vector3(runningEngine.position);
-    const currentRotation = () => Shapes.Vector3(runningEngine.rotation);
+    const TAU = 2 * Math.PI;
 
-    field position: Shapes.Vector3 = currentPosition();
-    field rotation: Shapes.Vector3 = currentRotation();
+    const currentPosition = () => u3(runningEngine.position);
+    const currentRotation = () => u3(runningEngine.rotation, 1/TAU);
+
+    field position: Shapes.ImmediateVector3 = currentPosition();
+    field rotation: Shapes.ImmediateVector3 = currentRotation();
 
     const refreshPeriod = Math.floor(1000 / 10);
     at ds {
         on message timer.PeriodicTick(refreshPeriod) => {
             const newPosition = currentPosition();
             const newRotation = currentRotation();
-            if (!is(Shapes.fromVector3(position.value), Shapes.fromVector3(newPosition))) {
+            if (!is(Shapes.fromImmediateVector3(position.value), Shapes.fromImmediateVector3(newPosition))) {
                 position.value = newPosition;
             }
-            if (!is(Shapes.fromVector3(rotation.value), Shapes.fromVector3(newRotation))) {
+            if (!is(Shapes.fromImmediateVector3(rotation.value), Shapes.fromImmediateVector3(newRotation))) {
                 rotation.value = newRotation;
             }
         }
@@ -128,7 +131,7 @@ async function enterScene(
                 on asserted SceneProtocol.Portal({
                     "name": o,
                     "destination": $dest: SceneProtocol.PortalDestination,
-                    "position": $targetPosition: Shapes.Vector3,
+                    "position": $targetPosition: Shapes.LiteralVector3,
                 }) => {
                     const newPos = new Vector3(targetPosition.x,
                                                targetPosition.y,
@@ -169,29 +172,46 @@ async function enterScene(
             }
         }
 
-        assert Shapes.Sprite({
+        const _POS = Symbol.for('pos');
+        const _HEAD = Symbol.for('head');
+        const _BODY = Symbol.for('body');
+
+        assert Shapes.Variable({ spriteName: id, variable: _POS, value: Shapes.fromImmediateVector3(position.value) });
+        assert Shapes.Variable({ spriteName: id, variable: _HEAD, value: Shapes.fromImmediateVector3(rotation.value) });
+        assert Shapes.Variable({ spriteName: id, variable: _BODY, value: Shapes.fromImmediateVector3({
+            x: Shapes.DoubleValue.immediate(0),
+            y: rotation.value.y,
+            z: Shapes.DoubleValue.immediate(0),
+        }) });
+
+        assert (() => {
+            const s = Shapes.Sprite({
             name: id,
+            formals: [_POS, _HEAD, _BODY],
             shape: B.nonphysical(
-                B.move(position.value, B.many([
-                    B.move({ x: 0, y: -0.9, z: 0 },
-                           B.rotate(scale3({ x: 0, y: rotation.value.y, z: 0 }, 1 / (2 * Math.PI)),
-                                    B.scale({ x: 0.4, y: 1.4, z: 0.1 }, B.box()))),
-                    B.rotate(scale3(rotation.value, 1 / (2 * Math.PI)),
-                             B.scale({ x: 0.15, y: 0.23, z: 0.18 }, B.many([
+                B.move(Shapes.Vector3.reference(_POS), B.many([
+                    B.move(u3v({x: 0, y: -0.9, z: 0}),
+                           B.rotate(Shapes.Vector3.reference(_BODY),
+                                    B.scale(u3v({x: 0.4, y: 1.4, z: 0.1}), B.box()))),
+                    B.rotate(Shapes.Vector3.reference(_HEAD),
+                             B.scale(u3v({x: 0.15, y: 0.23, z: 0.18}), B.many([
                                  B.box(),
-                                 B.move({ x: 0, y: 0, z: 0.501 },
+                                 B.move(u3v({x: 0, y: 0, z: 0.501}),
                                         B.texture(
                                             Shapes.TextureSpec.uvAlpha({
                                                 path: `https://www.gravatar.com/avatar/${md5(new TextEncoder().encode(email.value.trim()))}?s=256&d=wavatar`,
-                                                scale: Shapes.Vector2({ x:1, y:1 }),
-                                                offset: Shapes.Vector2({ x:0, y:0 }),
-                                                alpha: 1
+                                                scale: Shapes.Vector2.immediate(u2({ x:1, y:1 })),
+                                                offset: Shapes.Vector2.immediate(u2({ x:0, y:0 })),
+                                                alpha: Shapes.DoubleValue.immediate(1),
                                             }),
-                                            B.rotate({ x: 0, y: 0.5, z: 0 },
+                                            B.rotate(u3v({ x: 0, y: 0.5, z: 0 }),
                                                      B.plane()))),
                              ]))),
                 ]))),
-        });
+            });
+            console.log(s);
+            return s;
+        })();
     }
 }
 
@@ -265,7 +285,7 @@ window.addEventListener('load', async () => {
     Dataspace.boot(ds => {
         html.boot(ds);
         timer.boot(ds);
-        wsRelay.boot(ds, false);
+        wsRelay.boot(ds, true);
         wakeDetector.boot(ds);
         bootApp(ds, runningEngine);
     });
diff --git a/src/shapes.ts b/src/shapes.ts
index a4fb7a1..aa9b77b 100644
--- a/src/shapes.ts
+++ b/src/shapes.ts
@@ -20,10 +20,46 @@ import {
     Vector2,
     Vector3,
 } from '@babylonjs/core/Legacy/legacy';
-import { KeyedDictionary, Value, is } from "@syndicate-lang/core";
+import { Dataflow, IdentityMap, KeyedDictionary, Ref, Value, is } from "@syndicate-lang/core";
 
 import * as Shapes from './gen/shapes.js';
 
+export class Environment {
+    fields = new IdentityMap<symbol, Dataflow.Field<Value<Ref>>>();
+
+    constructor(
+        public spriteName: string,
+        public formals: symbol[],
+        public sceneDs: Ref,
+    ) {
+        formals.forEach(f => {
+            field v: Value<Ref> = false;
+            at this.sceneDs {
+                on asserted Shapes.Variable({
+                    "spriteName": this.spriteName,
+                    "variable": f,
+                    "value": $newValue,
+                }) => {
+                    console.log('Got value for', spriteName, f, newValue);
+                    v.value = newValue;
+                }
+            }
+            this.fields.set(f, v);
+        });
+    }
+
+    lookup(f: symbol, k: (v: Value<Ref>) => void) {
+        dataflow {
+            const v = this.fields.get(f);
+            if (v === void 0) throw new Error(`Lookup of ${f.description} in ${this.spriteName} failed`);
+            const w = v.value;
+            if (w !== false) k(w);
+        }
+    }
+}
+
+export type ValueK = (v: Value<Ref>) => void;
+
 export const activeFloorMeshes: Array<AbstractMesh> = [];
 export const activeTouchableMeshes: Array<AbstractMesh> = [];
 
@@ -50,13 +86,13 @@ export class ShapeTree<N extends Node = Node> {
         return this.subnodes.then(ns => [this.rootnode, ... ns]);
     }
 
-    reconcile(spriteName: string, name: string, shape: Shapes.Shape): ShapeTree {
+    reconcile(env: Environment, name: string, shape: Shapes.Shape): ShapeTree {
         if (is(Shapes.fromShape(shape), this.shapePreserve)) {
             return this;
         } else {
             this.remove();
-            return build(name, this.scene, shape, {
-                spriteName: async m => m.rootnode.metadata.spriteName = spriteName,
+            return build(env, name, this.scene, shape, {
+                spriteName: async m => m.rootnode.metadata.spriteName = env.spriteName,
                 collisions: async m => (await m.allnodes).forEach(n => n.checkCollisions = true),
             });
         }
@@ -82,20 +118,64 @@ export class ShapeTree<N extends Node = Node> {
     }
 }
 
-export function v2(v: Shapes.Vector2): Vector2 {
-    return new Vector2(v.x, v.y);
+export function dv(env: Environment, v: Shapes.DoubleValue, k: (v: number) => void) {
+    switch (v._variant) {
+        case "immediate": k(v.value); break;
+        case "reference": env.lookup(v.value, k as ValueK); break;
+    }
 }
 
-export function v3(v: Shapes.Vector3): Vector3 {
-    return new Vector3(v.x, v.y, v.z);
+export function u2(v: {x: number, y: number}): Shapes.ImmediateVector2 {
+    return Shapes.ImmediateVector2({
+        x: Shapes.DoubleValue.immediate(v.x),
+        y: Shapes.DoubleValue.immediate(v.y),
+    });
 }
 
-export function scale3(v: Shapes.Vector3, scale: number): Shapes.Vector3 {
-    return Shapes.Vector3({ x: v.x * scale, y: v.y * scale, z: v.z * scale });
+export function lv2(env: Environment, v: Shapes.ImmediateVector2, k: (v: Vector2) => void) {
+    dv(env, v.x, x => dv(env, v.y, y => k(new Vector2(x, y))));
 }
 
-export function q(q: Shapes.Quaternion): Quaternion {
-    return new Quaternion(q.a, q.b, q.c, q.d);
+export function v2(env: Environment, v: Shapes.Vector2, k: (v: Vector2) => void) {
+    switch (v._variant) {
+        case "immediate": lv2(env, v.value, k); break;
+        case "reference": env.lookup(v.value, v => lv2(env, Shapes.asImmediateVector2(v), k)); break;
+    }
+}
+
+export function u3(v: {x: number, y: number, z: number}, scale = 1): Shapes.ImmediateVector3 {
+    return Shapes.ImmediateVector3({
+        x: Shapes.DoubleValue.immediate(v.x * scale),
+        y: Shapes.DoubleValue.immediate(v.y * scale),
+        z: Shapes.DoubleValue.immediate(v.z * scale),
+    });
+}
+
+export function u3v(v: {x: number, y: number, z: number}, scale = 1): Shapes.Vector3 {
+    return Shapes.Vector3.immediate(u3(v, scale));
+}
+
+export function lv3(env: Environment, v: Shapes.ImmediateVector3, k: (v: Vector3) => void) {
+    dv(env, v.x, x => dv(env, v.y, y => dv(env, v.z, z => k(new Vector3(x, y, z)))));
+}
+
+export function v3(env: Environment, v: Shapes.Vector3, k: (v: Vector3) => void) {
+    switch (v._variant) {
+        case "immediate": lv3(env, v.value, k); break;
+        case "reference": env.lookup(v.value, v => lv3(env, Shapes.asImmediateVector3(v), k)); break;
+    }
+}
+
+export function lq(env: Environment, q: Shapes.ImmediateQuaternion, k: (v: Quaternion) => void) {
+    dv(env, q.a, a => dv(env, q.b, b => dv(env, q.c, c => dv(env, q.d, d =>
+        k(new Quaternion(a, b, c, d))))));
+}
+
+export function q(env: Environment, q: Shapes.Quaternion, k: (v: Quaternion) => void) {
+    switch (q._variant) {
+        case "immediate": lq(env, q.value, k); break;
+        case "reference": env.lookup(q.value, q => lq(env, Shapes.asImmediateQuaternion(q), k)); break;
+    }
 }
 
 export type MeshCustomizer = { [key: string]: ((m: ShapeTree<AbstractMesh>) => void) };
@@ -111,7 +191,7 @@ type CachedTexture = {
 };
 const textureCache = new KeyedDictionary<Value, CachedTexture>();
 
-function buildTexture(name: string, scene: Scene, spec: Shapes.TextureSpec): CachedTexture {
+function buildTexture(env: Environment, name: string, scene: Scene, spec: Shapes.TextureSpec): CachedTexture {
     const cacheKey = Shapes.fromTextureSpec(spec);
     const entry = textureCache.get(cacheKey);
     if (entry !== void 0) {
@@ -125,18 +205,18 @@ function buildTexture(name: string, scene: Scene, spec: Shapes.TextureSpec): Cac
         case "simple":
             break;
         case "uvAlpha":
-            mat.alpha = spec.alpha;
+            mat.alpha = 0;
+            dv(env, spec.alpha, a => mat.alpha = a);
             tex.hasAlpha = true;
             /* FALL THROUGH */
-        case "uv": {
-            const scale = v2(spec.scale);
-            const offset = v2(spec.offset);
-            tex.uScale = scale.x;
-            tex.vScale = scale.y;
-            tex.uOffset = offset.x;
-            tex.vOffset = offset.y;
+        case "uv":
+            v2(env, spec.scale, scale => v2(env, spec.offset, offset => {
+                tex.uScale = scale.x;
+                tex.vScale = scale.y;
+                tex.uOffset = offset.x;
+                tex.vOffset = offset.y;
+            }));
             break;
-        }
     }
     const newEntry = {
         key: cacheKey,
@@ -167,13 +247,7 @@ export function buildMesh(
     switch (meshSpec._variant) {
         case "Sphere": return { rootnode: MeshBuilder.CreateSphere(name, {}, scene) };
         case "Box": return { rootnode: MeshBuilder.CreateBox(name, {}, scene) };
-        case "Ground": {
-            const v = v2(meshSpec.value.size);
-            return {
-                rootnode: MeshBuilder.CreateGround(
-                    name, { width: v.x, height: v.y }, scene ?? void 0),
-            };
-        }
+        case "Ground": return { rootnode: MeshBuilder.CreateGround(name, {}, scene ?? void 0) };
         case "Plane": return { rootnode: MeshBuilder.CreatePlane(name, {}, scene) };
         case "External": {
             const rootnode = new Mesh(name, scene);
@@ -210,7 +284,7 @@ export function buildSound(name: string, scene: Scene, spec: Shapes.SoundSpec, s
     return new Sound(name, spec.url, scene, null, options);
 }
 
-export function build(name: string, scene: Scene, shape: Shapes.Shape, customize: MeshCustomizer): ShapeTree {
+export function build(env: Environment, name: string, scene: Scene, shape: Shapes.Shape, customize: MeshCustomizer): ShapeTree {
     switch (shape._variant) {
         case "Mesh": {
             const m = buildMesh(name, scene, shape.value);
@@ -219,23 +293,23 @@ export function build(name: string, scene: Scene, shape: Shapes.Shape, customize
             return t;
         }
 
-        case "Light":
-            return new ShapeTree(
-                scene,
-                shape,
-                new HemisphericLight(name, v3(shape.value.v), scene));
+        case "Light": {
+            const light = new HemisphericLight(name, new Vector3(0, 1, 0), scene);
+            v3(env, shape.value.v, v => light.direction = v);
+            return new ShapeTree(scene, shape, light);
+        }
 
         case "Scale": {
             const t = ShapeTree.transform(name, scene, shape);
-            t.rootnode.scaling = v3(shape.value.v);
-            build(name + '.inner', scene, shape.value.shape, customize).parent = t;
+            v3(env, shape.value.v, v => t.rootnode.scaling = v);
+            build(env, name + '.inner', scene, shape.value.shape, customize).parent = t;
             return t;
         }
 
         case "Move": {
             const t = ShapeTree.transform(name, scene, shape);
-            t.rootnode.position = v3(shape.value.v);
-            build(name + '.inner', scene, shape.value.shape, customize).parent = t;
+            v3(env, shape.value.v, v => t.rootnode.position = v);
+            build(env, name + '.inner', scene, shape.value.shape, customize).parent = t;
             return t;
         }
 
@@ -243,28 +317,30 @@ export function build(name: string, scene: Scene, shape: Shapes.Shape, customize
             const t = ShapeTree.transform(name, scene, shape);
             switch (shape.value._variant) {
                 case "euler":
-                    t.rootnode.rotation = v3(shape.value.v);
-                    t.rootnode.rotation.scaleInPlace(2 * Math.PI);
+                    v3(env, shape.value.v, v => {
+                        t.rootnode.rotation = v;
+                        t.rootnode.rotation.scaleInPlace(2 * Math.PI);
+                    });
                     break;
                 case "quaternion":
-                    t.rootnode.rotationQuaternion = q(shape.value.q);
+                    q(env, shape.value.q, q => t.rootnode.rotationQuaternion = q);
                     break;
             }
-            build(name + '.inner', scene, shape.value.shape, customize).parent = t;
+            build(env, name + '.inner', scene, shape.value.shape, customize).parent = t;
             return t;
         }
 
         case "many": {
             const t = ShapeTree.transform(name, scene, shape);
             shape.value.forEach((s, i) => {
-                build(name + '[' + i + ']', scene, s, customize).parent = t;
+                build(env, name + '[' + i + ']', scene, s, customize).parent = t;
             });
             return t;
         }
 
         case "Texture": {
-            const entry = buildTexture(name + '.texture', scene, shape.value.spec);
-            const t = build(name + '.inner', scene, shape.value.shape, {
+            const entry = buildTexture(env, name + '.texture', scene, shape.value.spec);
+            const t = build(env, name + '.inner', scene, shape.value.shape, {
                 ... customize,
                 material: async m => (await m.allnodes).forEach(n => n.material = entry.material),
             });
@@ -274,9 +350,13 @@ export function build(name: string, scene: Scene, shape: Shapes.Shape, customize
 
         case "Color": {
             const mat = new StandardMaterial(name + '.texture', scene);
-            mat.diffuseColor = new Color3(shape.value.r, shape.value.g, shape.value.b);
-            if (shape.value._variant === "transparent") mat.alpha = shape.value.alpha;
-            const t = build(name + '.inner', scene, shape.value.shape, {
+            dv(env, shape.value.r, r =>
+                dv(env, shape.value.g, g =>
+                    dv(env, shape.value.b, b => mat.diffuseColor = new Color3(r, g, b))));
+            if (shape.value._variant === "transparent") {
+                dv(env, shape.value.alpha, a => mat.alpha = a);
+            }
+            const t = build(env, name + '.inner', scene, shape.value.shape, {
                 ... customize,
                 material: async m => (await m.allnodes).forEach(n => n.material = mat),
             });
@@ -286,7 +366,7 @@ export function build(name: string, scene: Scene, shape: Shapes.Shape, customize
 
         case "Sound": {
             const sound = buildSound(name + ".sound", scene, shape.value.spec, true);
-            const t = build(name + ".inner", scene, shape.value.shape, {
+            const t = build(env, name + ".inner", scene, shape.value.shape, {
                 ... customize,
                 sound: async m => sound.attachToMesh(m.rootnode),
             });
@@ -295,10 +375,10 @@ export function build(name: string, scene: Scene, shape: Shapes.Shape, customize
         }
 
         case "Name":
-            return build(name + '.' + shape.value.base, scene, shape.value.shape, customize);
+            return build(env, name + '.' + shape.value.base, scene, shape.value.shape, customize);
 
         case "Floor":
-            return build(name, scene, shape.value.shape, {
+            return build(env, name, scene, shape.value.shape, {
                 ... customize,
                 floor: async m => {
                     const nodes = await m.allnodes;
@@ -311,13 +391,13 @@ export function build(name: string, scene: Scene, shape: Shapes.Shape, customize
             });
 
         case "Nonphysical":
-            return build(name, scene, shape.value.shape, {
+            return build(env, name, scene, shape.value.shape, {
                 ... customize,
                 collisions: async m => (await m.allnodes).forEach(n => n.checkCollisions = false),
             });
 
         case "Touchable":
-            return build(name, scene, shape.value.shape, {
+            return build(env, name, scene, shape.value.shape, {
                 ... customize,
                 touchable: async m => {
                     const nodes = await m.allnodes;
@@ -426,23 +506,30 @@ export function buildCSG(name: string, scene: Scene, expr: Shapes.CSGExpr): Buil
     };
 }
 
-export const builder: { [key: string]: (... args: any[]) => Shapes.Shape } = {
+export const builder = {
     sphere: () => Shapes.Shape.Mesh(Shapes.Mesh.Sphere(Shapes.Sphere())),
     box: () => Shapes.Shape.Mesh(Shapes.Mesh.Box(Shapes.Box())),
     plane: () => Shapes.Shape.Mesh(Shapes.Mesh.Plane(Shapes.Plane())),
-    ground: (v: Shapes.Vector2) => Shapes.Shape.Mesh(Shapes.Mesh.Ground(Shapes.Ground(Shapes.Vector2(v)))),
-    light: (v: Shapes.Vector3) => Shapes.Shape.Light(Shapes.Light(Shapes.Vector3(v))),
-    scale: (v: Shapes.Vector3, shape: Shapes.Shape) => Shapes.Shape.Scale(Shapes.Scale({ v: Shapes.Vector3(v), shape })),
-    move: (v: Shapes.Vector3, shape: Shapes.Shape) => Shapes.Shape.Move(Shapes.Move({ v: Shapes.Vector3(v), shape })),
-    rotate: (v: Shapes.Vector3, shape: Shapes.Shape) => Shapes.Shape.Rotate(Shapes.Rotate.euler({ v: Shapes.Vector3(v), shape })),
+    ground: () => Shapes.Shape.Mesh(Shapes.Mesh.Ground(Shapes.Ground())),
+    light: (v: Shapes.Vector3) => Shapes.Shape.Light(Shapes.Light(v)),
+    scale: (v: Shapes.Vector3, shape: Shapes.Shape) => Shapes.Shape.Scale(Shapes.Scale({ v, shape })),
+    move: (v: Shapes.Vector3, shape: Shapes.Shape) => Shapes.Shape.Move(Shapes.Move({ v, shape })),
+    rotate: (v: Shapes.Vector3, shape: Shapes.Shape) => Shapes.Shape.Rotate(Shapes.Rotate.euler({ v, shape })),
     many: (shapes: Shapes.Shape[]) => Shapes.Shape.many(shapes),
     texture: (spec: Shapes.TextureSpec, shape: Shapes.Shape) => Shapes.Shape.Texture(Shapes.Texture({ spec, shape })),
-    color: (r: number, g: number, b: number, shape: Shapes.Shape, alpha = 1.0) => {
-        return Shapes.Shape.Color((alpha === 1.0)
+    color: (r0: number | symbol, g0: number | symbol, b0: number | symbol, shape: Shapes.Shape, alpha0: number | symbol = 1.0) => {
+        function vd(x: number | symbol): Shapes.DoubleValue {
+            return typeof x === 'number' ? Shapes.DoubleValue.immediate(x) : Shapes.DoubleValue.reference(x);
+        }
+        const r = vd(r0);
+        const g = vd(g0);
+        const b = vd(b0);
+        const alpha = vd(alpha0);
+        return Shapes.Shape.Color((alpha0 === 1.0)
             ? Shapes.Color.opaque({ r, g, b, shape })
             : Shapes.Color.transparent({ r, g, b, alpha, shape }));
     },
     name: (base: string, shape: Shapes.Shape) => Shapes.Shape.Name(Shapes.Name({ base, shape })),
     floor: (shape: Shapes.Shape) => Shapes.Shape.Floor(Shapes.Floor(shape)),
     nonphysical: (shape: Shapes.Shape) => Shapes.Shape.Nonphysical(Shapes.Nonphysical(shape)),
-};
+} satisfies { [key: string]: (... args: any[]) => Shapes.Shape };