The Professor's Cube (also known as the 5×5×5 Rubik's Cube and many other names, depending on manufacturer) is a 5×5×5 version of the original Rubik's Cube. It has qualities in common with both the 3×3×3 Rubik's Cube and the 4×4×4 Rubik's Revenge, and solution strategies for both can be applied. History The Professor's Cube was invented by Udo Krell in 1981. Out of the many designs that were proposed, Udo Krell's design was the first 5×5×5 design that was manufactured and sold. Uwe Mèffert manufactured the cube and sold it in Hong Kong in 1983. Ideal Toys, who first popularized the original 3x3x3 Rubik's cube, marketed the puzzle in Germany as the "Rubik's Wahn" (German for illusion or delusion). When the cube was marketed in Japan, it was marketed under the name "Professor's Cube". Mèffert reissued the cube under the name "Professor's Cube" in the 1990s. The early versions of the 5×5×5 cube sold at Barnes & Noble were marketed under the name "Professor's Cube" but currently, Barnes and Noble sells cubes that are simply called "5×5 Cube." Mefferts.com used to sell a limited edition version of the 5×5×5 cube called the Professor's Cube. This version had colored tiles rather than stickers. Verdes Innovations sells a version called the V-Cube 5. Workings The original Professor's Cube design by Udo Krell works by using an expanded 3×3×3 cube as a mantle with the center edge pieces and corners sticking out from the spherical center of identical mechanism to the 3×3×3 cube. All non-central pieces have extensions that fit into slots on the outer pieces of the 3×3×3, which keeps them from falling out of the cube while making a turn. The fixed centers have two sections (one visible, one hidden) which can turn independently. This feature is unique to the original design. The Eastsheen version of the puzzle uses a different mechanism. The fixed centers hold the centers next to the central edges in place, which in turn hold the outer edges. The non-central edges hold the corners in place, and the internal sections of the corner pieces do not reach the center of the cube. The V-Cube 5 mechanism, designed by Panagiotis Verdes, has elements in common with both. The corners reach to the center of the puzzle (like the original mechanism) and the center pieces hold the central edges in place (like the Eastsheen mechanism). The middle edges and