     [ x, y ] = @edgePoint a
     @drawCircle x, y, @eyeSize, 'black'
   drawTail: ->
-    a = @angle + Math.PI
+    a = @angle + pi
     [ x1, y1 ] = @edgePoint a
     [ x2, y2 ] = @edgePoint a, @radius + @tailSize
     c = @ctx()

  margins: ->
    m = @marges ?= []
    return m if m.length
    fi = Math.PI * @visualAngle() / 2
    t1 = @angle - fi
    t1 = @universe.tp( Math.sin(t1), Math.cos(t1) )
    t2 = @angle + fi

  drawEar: (left) ->
    point = @angle + if left then -qt else qt
    rad = @earSize
    [ start, end ] = if left then [ @angle, @angle + pi ] else [ @angle - pi, @angle ]
    [ x, y ] = @edgePoint point, rad + @radius
    @drawArc x, y, rad, @bodyColor, start, end
  calcTailSize: ->
