anchor.diff:      let [<Fact>] entitySubscribeWorks () =
           let world = World.makeDefault ()
           let handleEvent = fun evt world -> (Cascade, World.updateUserState (fun _ -> evt.Subscriber) world)
  -        let world = World.subscribe handleEvent StringEvent Simulants.DefaultEntity world
  -        let world = World.publish String.Empty StringEvent EventTrace.empty Simulants.Game world
  -        Assert.Equal<Simulant> (Simulants.DefaultEntity :> Simulant, World.getUserState world)
  +        let world = World.subscribe handleEvent StringEvent DefaultEntity world
  +        let world = World.publish String.Empty StringEvent EventTrace.empty Game world
  +        Assert.Equal<Simulant> (DefaultEntity :> Simulant, World.getUserState world)
   
       let [<Fact>] gameSerializationWorks () =
           let world = World.makeDefault ()
           let oldWorld = world
           World.writeGameToFile TestFilePath world
           let world = World.readGameFromFile TestFilePath world
  -        Assert.Equal<Name> (Simulants.DefaultScreen.GetName oldWorld, Simulants.DefaultScreen.GetName world)
  -        Assert.Equal<Name> (Simulants.DefaultGroup.GetName oldWorld, Simulants.DefaultGroup.GetName world)
  -        Assert.Equal<Name> (Simulants.DefaultEntity.GetName oldWorld, Simulants.DefaultEntity.GetName world)
  +        Assert.Equal<Name> (DefaultScreen.GetName oldWorld, DefaultScreen.GetName world)
  +        Assert.Equal<Name> (DefaultGroup.GetName oldWorld, DefaultGroup.GetName world)
  +        Assert.Equal<Name> (DefaultEntity.GetName oldWorld, DefaultEntity.GetName world)
   
       let [<Fact>] iterativeFrpWorks () =
           let world = World.makeDefault ()
  -        let world = World.createEntity typeof<EntityDispatcher>.Name None (Some Jim.EntityName) Simulants.DefaultGroup world |> snd
  -        let world = World.createEntity typeof<EntityDispatcher>.Name None (Some Bob.EntityName) Simulants.DefaultGroup world |> snd
  +        let world = World.createEntity typeof<EntityDispatcher>.Name None (Some Jim.EntityName) DefaultGroup world |> snd
  +        let world = World.createEntity typeof<EntityDispatcher>.Name None (Some Bob.EntityName) DefaultGroup world |> snd
           let world = !-- Bob.Visible --- map not --> Jim.Visible ^ world
           let world = Bob.SetVisible false world
           Assert.False (Bob.GetVisible world)
  
positive.code: 
      let [<Fact>] iterativeFrpCyclicWorks () =
          let world = World.makeDefault ()
          let world = World.createEntity typeof<EntityDispatcher>.Name None (Some Jim.EntityName) Simulants.DefaultGroup world |> snd
          let world = World.createEntity typeof<EntityDispatcher>.Name None (Some Bob.EntityName) Simulants.DefaultGroup world |> snd
          let world = !-- Bob.Visible --> Jim.Visible ^ world
          let world = !-- Jim.Visible -/> Bob.Visible ^ world
          let world = Bob.SetVisible false world
  
negative.code: open Prime
  open Prime.Stream
  open Nu
  open Nu.Simulants
  module WorldTests =
  
      let TestFilePath = "TestFile.nugame"
      let StringEvent = stoa<string> "String/Event"
      let Jim = DefaultGroup => "Jim"
      let Bob = DefaultGroup => "Bob"
  
      let [<Fact>] runOneFrameThenCleanUp () =
          let world = World.makeEmpty ()
  