anchor.diff:      context.Rect(0., 0., float width, float height)
       context.FillStyle <- "rgb(0, 0, 0)"
       context.Fill()
  +
  +  module PlayerBullet =
  +
  +    [<JavaScript>]
  +    let draw (context : CanvasRenderingContext2D) bullets =
  +      bullets
  +      |> List.iter(fun bullet ->
  +        context.Save()
  +        context.BeginPath()
  +        context.Translate(bullet.x, bullet.y)
  +        context.MoveTo(0., -4.)
  +        context.LineTo(0., 4.)
  +        context.StrokeStyle <- "rgb(255, 0, 0)"
  +        context.LineWidth <- 4.0
  +        context.LineCap <- LineCap.Round
  +        context.Stroke()
  +        context.Restore()
  +      )
   
     module PlayerShip =
   
  
positive.code:     let context = canvas.GetContext "2d"
      
      // ソケットの準備
      let playerShipSocket = PlayerShip.initSocket context
  
      Div [ Width (string width); Attr.Style "float:left" ] -< [
        Div [ Attr.Style "float:center" ] -< [
  
negative.code:   type Mover = {
      x : float
      y : float
    }
  
    type Info = {
      playerShip : Mover
      bullets : Mover list
    }
  
    [<JavaScript>]
  