docs: function(opt_randFunc) {
      var randFunc = opt_randFunc || randInt;
      var strong = randFunc(3);
      var colors = [];
      for (var ii = 0; ii < 3; ++ii) {
        colors.push(randFunc(128) + (ii === strong ? 128 : 64));
      }
      return "rgb(" + colors.join(",") + ")";
    }