Filling a void in Crayola's line, Jetson introduces a rainbow crayon enabling one to create a rainbow using just one stroke. This sure is an improvement over having to align seperate red, yellow and blue crayon strokes and having them blend together to produce the orange and green. Jetson produces the crayon by placing red, yellow, and blue wax sticks in a mold which is heated and then vibrated to blend the colors while the wax is molten. The secret is precisely controlling the amplitude and frequency of the vibration in the direction of the blend which in turn depends on the weight of the wax and mold and viscosity of the heated wax. The cool down process has to be precise also to retain the blending of colors. Widths of 12, 18 and 25 mm are in the package. You can get smaller widths by holding the crayons at an angle to the direction of the stroke. You can get larger widths by cutting the tip at an angle instead of the supplied 90 degree cut.