Soma cube cube problem. There are 240 distinct solutions of the Soma cube puzzle, excluding rotations and reflections: these are easily generated by a simple recursive backtracking search computer program similar to that used for the eight queens puzzle. Current world record for the fastest time to solve a soma cube is 2.93 seconds and was set by Krishnam Raju Gadiraju, India. The seven Soma pieces are six polycubes of order four, and one of order three: Piet Hein authorized a finely crafted rosewood version of the Soma cube manufactured by Theodor Skjøde Knudsen's company Skjøde Skjern (of Denmark). Beginning in about
Square-1 (puzzle) shapes are possible for the middle layer, there is a quick sequence of twists which changes the shape of the middle layer from one to the other without touching the rest of the puzzle. Once the puzzle has a cube shape, the upper and lower layers are cut in an Iron Cross-like fashion, or equivalently cut by two concentric (standard) crosses, that make an angle with each other. Like Rubik's Cube, the pieces are colored. For the puzzle to be solved, not only does it need to be in cube shape, but each face of the cube must also have