   Verlet Spring
 ###
 class Spring
-  a: null # first particle
-  b: null # second particle
-  restLength: 0
-  strength: 0.5
-
   constructor: (@a, @b, @strength = 0.5) ->
     @restLength = @a.position.distance @b.position
 


  # created with a reference to the original physics particle array
  constructor: (@physics) ->

  update: ->
    if timer is -1 or timer >= @interval

  Particle Emitter
###
class Emitter

  # local vars
  timer = -1
