     @type      = Thing
     @others    = {}
     @outlined  = false
+    @marges    = null
     unless @dontAdd
       uni = @universe
       uni.change = true

      return if isAbove then QT else 3 * QT
    if @y == t.y
      return if isBefore then 0 else PI
    theta = PI * acos abs( @x - t.x ) / @dist(t)
    theta = if isAbove
      if isBefore then theta else PI - theta
    else
      if isBefore then TAU - theta else PI + theta
    degrees theta

class Stone extends Thing
  constructor: ( location, options = {} ) ->

  margins: ->
    m = @marges ?= []
    return m if m.length
    fi = PI * @visualAngle()
    t1 = @angle - fi
    t1 = @universe.tp( sin(t1), cos(t1) )
    t2 = @angle + fi
