code: function valueToPoint (value, index, total) {
    var x     = 0
    var y     = -value * 0.8
    var angle = Math.PI * 2 / total * index
    var cos   = Math.cos(angle)
    var sin   = Math.sin(angle)
    var tx    = x * cos - y * sin + 100
    var ty    = x * sin + y * cos + 100
    return {
      x: tx,
      y: ty
    }
  }
docs: math helper...