? <Scene ?name ?scene> [
  $scene [
    ? <Exit ?spriteName ?roomName> <Exit $spriteName $roomName <v 0.0 0.0 0.0>>
    ? <Exit ?spriteName ?roomName ?initialPos> [
      $config ? <Scene $roomName ?ds> [
        $scene <portal $spriteName $ds $initialPos>
      ]
    ]
    ? <portal ?spriteName ?target> <portal $spriteName $target <v 0.0 0.0 0.0>>
  ]
]