   MAX_MASS = 10
   PAN_SPEED = 10
   ROTATE_SPEED = 0.01
+  SCALE_SPEED = 1.1
 
   width = window.innerWidth
   height = window.innerHeight
   offset = new Vector(0, 0)
   rotation = 0
+  scale = 1
 
   $('canvas').attr 'width', width
   $('canvas').attr 'height', height

      particle.render ctx

    ctx.translate width/2, height/2
    ctx.rotate -rotation
    ctx.translate -width/2, -height/2
    ctx.translate -offset.x, -offset.y


  $(window).keydown (e) ->
    e.preventDefault()
    if e.keyCode == 88
      scale *= SCALE_SPEED
    if e.keyCode == 90
      scale /= SCALE_SPEED
    if e.keyCode == 81
      rotation -= ROTATE_SPEED
    if e.keyCode == 69
