anchor.diff:                  just avatar
   
               | SynchronizeBounds ->
  -                
  +
                   // synchronize bounds
                   let avatar = Avatar.updateBounds (constant (entity.GetBounds world)) avatar
                   just avatar
  
positive.code:              entity.BodyShape == bodyShapes]
  
          override this.Channel (_, entity) =
              [entity.UpdateEvent => msg Update
               entity.UpdateEvent =|> fun _ ->
                  let force = v2Zero
                  let force = if KeyboardState.isKeyDown KeyboardKey.Right then v2 Constants.Field.WalkForce 0.0f + force else force
  
negative.code:                 elif KeyboardState.isKeyDown KeyboardKey.Up then msg (Face Upward)
                  elif KeyboardState.isKeyDown KeyboardKey.Down then msg (Face Downward)
                  else msg Nil
               entity.UpdateEvent => msg Update
               entity.Parent.PostUpdateEvent => msg SynchronizeBounds
               entity.Parent.PostUpdateEvent => msg PostUpdate
               entity.CollisionEvent =|> fun evt -> msg (Collision evt.Data)
               entity.SeparationEvent =|> fun evt -> msg (Separation evt.Data)]
  
  