       timeScale *= TIME_SCALE_SPEED
     if e.keyCode == 189
       timeScale /= TIME_SCALE_SPEED
-    if e.keyCode == 88
-      scale *= SCALE_SPEED
-    if e.keyCode == 90
-      scale /= SCALE_SPEED
     if e.keyCode == 37 || e.keyCode == 65
       offset = offset.add new Vector(PAN_SPEED, 0)
     if e.keyCode == 38 || e.keyCode == 87


    rotation += ROTATE_SPEED * deltaTime if Keyboard.isDown 69
    rotation -= ROTATE_SPEED * deltaTime if Keyboard.isDown 81

    ctx.clearRect 0, 0, width, height
    ctx.translate width/2, height/2

  MAX_MASS = 10
  PAN_SPEED = 10
  ROTATE_SPEED = 0.001
  SCALE_SPEED = 0.001
  TIME_SCALE_SPEED = 1.1

  width = window.innerWidth
