The colors in this puzzle have been arranged to suggest that there exists no precise point on the chromatic scale at which one color becomes another. The puzzle can be considered complete even when its pieces are disassembled and mixed together in the box. The large version of the original Gradient Puzzle is a three color blend of a reflective metallic ink and two spot colors. Recommended for ages 12 and up. Completed 1000 piece puzzle is 20 x 28 inches.