code: function nColours (N, sat, light) {
    sat = sat || 100; light = light || 50
    var a = []
    for(var i = 0; i < N; i++) {
      //convert to rgb because node-canvas doesn't support hsl
      a.push(Color('hsl('+ ~~(i*(360/N)) + ', ' + sat + '%, ' + light +'%)').rgbString())
    }
    return a
  }
docs: /*
  now, we can only support 2 scales, maximum.
  (to be drawn on the left and the right side)