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
Nine-Colour Cube one corner, one edge and one face centre each. The puzzle has eight corner pieces, which can be permutated in 8! different ways, and twelve edge pieces, which can be permutated in 12! ways. The position of the face centre pieces is fixed, therefore there is only one possible permutation for the face centres. Since all cubies only consist of one colour (unlike on the Rubik's Cube), they have no visible orientation and therefore this is not taken into account. The exact number of combinations is not yet reached because of several constraints: As some pieces are identical to each