     @x = d3.scale.linear().domain([0, max_x]).range([0, @width])
     @y = d3.scale.linear().domain([0, max_y]).range([0, @height])
 
-    @colors = d3.scale.category20c()
-
     @nodes = @svg.selectAll('g.node')
       .data(@nodes, (d) -> d.key)
       .enter()

    @nodes.append('svg:rect')
      .attr('width', @x 70)
      .attr('height', @y 50)
      .attr('fill', (d, i) => @colors i)
      .attr('data-tooltip', (d) -> d.key)

    @make_line = d3.svg.line()

    @x = attrs.x
    @y = attrs.y
    @key = attrs.key
    @fill_color = attrs.fill_color
    @stroke_color = attrs.stroke_color

  # returns true if the node hasn't good coordinates
  bad_node: =>
