anchor.diff:      Async.Start(gameLoop(), cts.Token)
   
   let stop() = 
  -    cts.Cancel()+    cts.Cancel()
  
positive.code:         body (
              let universe = !~"universe"
              let rec loop (state:Spaceship) = messageHandler {
                  let! msg = Message.receive None
                  let state =
                      match msg with
                      | MoveLeft -> { state with Position = { state.Position with X = (max 0 (state.Position.X - 1)) }}
  
negative.code:         name "universe"
          body (
              let rec loop (state:UniverseState) = messageHandler {
                  let! msg = Message.receive ()
                  let state =
                      match msg with
                      | ItemUpdate(id, x) ->
  