diff --git a/prospect/examples/all-pairs-shortest-paths/all-pairs-shortest-paths.rb b/prospect/examples/all-pairs-shortest-paths/all-pairs-shortest-paths.rb
new file mode 100644
index 0000000..3ef755e
--- /dev/null
+++ b/prospect/examples/all-pairs-shortest-paths/all-pairs-shortest-paths.rb
@@ -0,0 +1,45 @@
+# ShortestPaths example, from figure 1 of "Logic and lattices for
+# distributed programming", Conway et. al, UCB tech report, 2012
+#
+# Modified slightly:
+#  - added "bootstrap" section to give the algorithm some data
+#  - added "stdio <~ ..." to monitor results
+#  - added boilerplate to kickstart the program
+#
+# Problem: doesn't terminate or yield output, because cycles exist in
+# the input.
+
+require 'rubygems'
+require 'bud'
+
+class ShortestPaths
+  include Bud
+
+  state do
+    table :link, [:from, :to] => [:cost]
+    scratch :path, [:from, :to, :next_hop, :cost]
+    scratch :min_cost, [:from, :to] => [:cost]
+  end
+
+  bootstrap do
+    link <= [[1, 3, -2],
+             [2, 1, 4],
+             [2, 3, 3],
+             [3, 4, 2],
+             [4, 2, -1]]
+  end
+
+  bloom do
+    path <= link {|l| [l.from, l.to, l.to, l.cost]}
+    path <= (link*path).pairs(:to => :from) do |l,p|
+      [l.from, p.to, l.to, l.cost + p.cost]
+    end
+    min_cost <= path.group([:from, :to], min(:cost))
+
+    stdio <~ path { |p| ["path" + p.to_s] }
+    stdio <~ min_cost { |m| ["min_cost" + m.to_s] }
+  end
+end
+
+program = ShortestPaths.new()
+program.run_fg
diff --git a/prospect/examples/all-pairs-shortest-paths/all-pairs-shortest-paths.rkt b/prospect/examples/all-pairs-shortest-paths/all-pairs-shortest-paths.rkt
new file mode 100644
index 0000000..7e0fbb0
--- /dev/null
+++ b/prospect/examples/all-pairs-shortest-paths/all-pairs-shortest-paths.rkt
@@ -0,0 +1,46 @@
+#lang prospect
+;; After Figure 1 in "Logic and lattices for distributed programming",
+;; Conway et. al, UCB tech report, 2012
+;;
+;; Quasi-problem: doesn't terminate, because cycles exist in the
+;; input.
+
+(require racket/set)
+(require prospect/actor)
+
+(struct link (from to cost) #:prefab)
+(struct path (from to cost) #:prefab)
+(struct path-exists (from to) #:prefab) ;; Hmm.
+(struct min-cost (from to cost) #:prefab)
+
+(actor (forever (assert (link 1 3 -2))
+                (assert (link 2 1 4))
+                (assert (link 2 3 3))
+                (assert (link 3 4 2))
+                (assert (link 4 2 -1))))
+
+(actor (forever (during (link $from $to $cost)
+                        (assert (path-exists from to))
+                        (assert (path from to cost)))))
+
+(actor (forever (during (link $A $B $link-cost)
+                        (during (path B $C $path-cost)
+                                (assert (path-exists A C))
+                                (assert (path A C (+ link-cost path-cost)))))))
+
+(actor (forever (during (path-exists $from $to)
+                        #:collect [(costs (set)) (least +inf.0)]
+                        (assert (min-cost from to least))
+                        (on (asserted (path from to $cost))
+                            (values (set-add costs cost)
+                                    (min least cost)))
+                        (on (retracted (path from to $cost))
+                            (define new-costs (set-remove costs cost))
+                            (values new-costs
+                                    (for/fold [(least +inf.0)] [(x new-costs)] (min x least)))))))
+
+;; (actor (forever (during (path $from $to $cost)
+;;                         #:init [(displayln `(+ ,(path from to cost)))]
+;;                         #:done [(displayln `(- ,(path from to cost)))])))
+(actor (forever (on (asserted (min-cost $from $to $cost))
+                    (displayln (min-cost from to cost)))))
diff --git a/prospect/examples/all-pairs-shortest-paths/all-pairs-shortest-paths2.rb b/prospect/examples/all-pairs-shortest-paths/all-pairs-shortest-paths2.rb
new file mode 100644
index 0000000..158991d
--- /dev/null
+++ b/prospect/examples/all-pairs-shortest-paths/all-pairs-shortest-paths2.rb
@@ -0,0 +1,44 @@
+# ShortestPaths example, from figure 1 of "Logic and lattices for
+# distributed programming", Conway et. al, UCB tech report, 2012
+#
+# Modified slightly:
+#  - added "bootstrap" section to give the algorithm some data
+#  - added "stdio <~ ..." to monitor results
+#  - added boilerplate to kickstart the program
+#  - repurposed next_hop field to track seen-set to avoid nontermination
+
+require 'rubygems'
+require 'bud'
+require 'set'
+
+class ShortestPaths
+  include Bud
+
+  state do
+    table :link, [:from, :to] => [:cost]
+    scratch :path, [:from, :to, :seen, :cost]
+    scratch :min_cost, [:from, :to] => [:cost]
+  end
+
+  bootstrap do
+    link <= [[1, 3, -2],
+             [2, 1, 4],
+             [2, 3, 3],
+             [3, 4, 2],
+             [4, 2, -1]]
+  end
+
+  bloom do
+    path <= link {|l| [l.from, l.to, Set.new.add(l.from).add(l.to), l.cost]}
+    path <= (link*path).pairs(:to => :from) do |l,p|
+      [l.from, p.to, p.seen.clone.add(l.from), l.cost + p.cost] if not p.seen.include?(l.from)
+    end
+    min_cost <= path.group([:from, :to], min(:cost))
+
+    stdio <~ path { |p| ["path" + p.to_s] }
+    stdio <~ min_cost { |m| ["min_cost" + m.to_s] }
+  end
+end
+
+program = ShortestPaths.new()
+program.run_fg
diff --git a/prospect/examples/all-pairs-shortest-paths/all-pairs-shortest-paths2.rkt b/prospect/examples/all-pairs-shortest-paths/all-pairs-shortest-paths2.rkt
new file mode 100644
index 0000000..26321df
--- /dev/null
+++ b/prospect/examples/all-pairs-shortest-paths/all-pairs-shortest-paths2.rkt
@@ -0,0 +1,44 @@
+#lang prospect
+;; After Figure 1 in "Logic and lattices for distributed programming",
+;; Conway et. al, UCB tech report, 2012
+
+(require racket/set)
+(require prospect/actor)
+
+(struct link (from to cost) #:prefab)
+(struct path (from to seen cost) #:prefab)
+(struct path-exists (from to) #:prefab) ;; Hmm.
+(struct min-cost (from to cost) #:prefab)
+
+(actor (forever (assert (link 1 3 -2))
+                (assert (link 2 1 4))
+                (assert (link 2 3 3))
+                (assert (link 3 4 2))
+                (assert (link 4 2 -1))))
+
+(actor (forever (during (link $from $to $cost)
+                        (assert (path-exists from to))
+                        (assert (path from to (set from to) cost)))))
+
+(actor (forever (during (link $A $B $link-cost)
+                        (during (path B $C $seen $path-cost)
+                                (assert #:when (not (set-member? seen A)) (path-exists A C))
+                                (assert #:when (not (set-member? seen A))
+                                        (path A C (set-add seen A) (+ link-cost path-cost)))))))
+
+(actor (forever (during (path-exists $from $to)
+                        #:collect [(costs (set)) (least +inf.0)]
+                        (assert (min-cost from to least))
+                        (on (asserted (path from to _ $cost))
+                            (values (set-add costs cost)
+                                    (min least cost)))
+                        (on (retracted (path from to _ $cost))
+                            (define new-costs (set-remove costs cost))
+                            (values new-costs
+                                    (for/fold [(least +inf.0)] [(x new-costs)] (min x least)))))))
+
+(actor (forever (during (path $from $to $seen $cost)
+                        #:init [(displayln `(+ ,(path from to seen cost)))]
+                        #:done [(displayln `(- ,(path from to seen cost)))])))
+(actor (forever (on (asserted (min-cost $from $to $cost))
+                    (displayln (min-cost from to cost)))))