Happy Cube Expert is the most difficult puzzle in the Happy Cube family! A fun 3D game in beautiful, marbled foam. Each cube has a different shape, colour, and solution. Ready for a real challenge? Try the purple puzzle and feel like Albert Einstein! The 6 Expert think-boxes are named after famous scientists. The information provided here is as complete and accurate as possible; however, product names, colours and/or materials are subject to change without notice.