code: function(color1, color2, factor) {
  		if (arguments.length < 3) { factor = 0.5; }
  		var result = color1.slice();
  		for (var i=0;i<3;i++) {
  			result[i] = Math.round(result[i] + factor*(color2[i]-color1[i]));
  		}
  		return result;
  	}
docs: Interpolate (blend) two colors with a given factor
  @param {number[]} color1
  @param {number[]} color2
  @param {float} [factor=0.5] 0..1
  @returns {number[]}