       @y /= l
     this
 
+  normalize_: -> @clone().normalize()
+
   normalizeTo: (length) ->
     magnitude = Math.sqrt(@x * @x + @y * @y)
     if magnitude > 0

      @z /= l
    this

  normalizeTo: (length) ->
    magnitude = Math.sqrt(@x * @x + @y * @y + @z * @z)
    if magnitude > 0

      @x *= magnitude
      @y *= magnitude
    this

  normalizeTo_: (length) -> @clone().normalizeTo_(length)

  distance: (v) -> Math.sqrt @distanceSquared2(v.x, v.y)
  distanceSquared: (v) -> @distanceSquared2 v.x, v.y
