The Fully Functional 5x5x4 Cube is made with a hard black plastic core. The purpose of this puzzle is to scramble up all 6 faces and then return it so that each side only has one color on it. The unique thing about this puzzle is that although it is 5 layers deep in two directions, it is 4 layers deep in the third. Although it takes on a rectangular shape, it is still completely functional. The do-it-yourself feature allows for you to customize your color pattern however you like. The Fully Functional 5x5x4 is manufactured by Ayi’s Toy.

• See at Puzzle Master