You can make cutout tapers from regular taper candles fairly easily. Do this by dipping your taper in one color of wax until it is approximately ½″ in diameter (or, depending on the size of the finished candle, thicker). Next, dip the taper into a second color until you have built up the wax to another ½″ thickness (or more).
You can make a simple two-color cutout taper by cutting through the outer layer of colored wax with a sharp knife, incising any design that suits your fancy — such as squares, triangles, circles, or flower shapes. Or, you can make a multicolored cutout taper by continuing to dip the taper into different colors of wax (you will need a separate container for each color) until you have built up several layers of different colors. This will make a thicker taper than the usual. Then, using the same procedure, cut through the colored layers so that all of the different colors show through.
Don't make the cuts in your cutout candle too deep — if you cut too far into the core, the candle will tend to droop when the flame reaches the incised parts. Starting with a thick taper and using fairly thin outer coatings will help prevent this problem.