code: function verbColor(verbs, verb) {
      var index = verbs.indexOf(verb),
          color = (index >= 0) ? VERB_COLORS(index) : "#ccc",
          rgb = d3.rgb(color);
      return "rgba(" + rgb.r + "," + rgb.g + "," + rgb.b + ",0.5)"
    }
docs: Return color for a verb.  verbs - Top verbs, order of which determines color verb  - The verb you're looking to color  Returns color suitable for styling an element (rgba).