Rubik's Domino is a hand-held puzzle similar to a Rubik's Cube. However, it has one layer removed, making it a 2×3×3

cuboid In geometry, a cuboid is a hexahedron with quadrilateral faces, meaning it is a polyhedron with six Face (geometry), faces; it has eight Vertex (geometry), vertices and twelve Edge (geometry), edges. A ''rectangular cuboid'' (sometimes also calle ...

. The 3×3 faces can be turned 90-degrees as normal, but the 2×3 faces can only be turned 180 degrees. Other cuboids of 2×2×n (if n is an even number) will solve like multiple

dominoes Dominoes is a family of tile-based games played with gaming pieces. Each domino is a rectangular tile, usually with a line dividing its face into two square ''ends''. Each end is marked with a number of spots (also called ''Pip (counting), pips ...

at once. When only using pairs of turns, the puzzle may be solved similarly to a 3x3. The original version had white and black plastic layers. Each 3×3 face displayed a number of dots from 1–9. More recent versions use the traditional six-colour scheme, as seen on most other twisty puzzles. It has 406,425,600 potential positions and any position can be made into a solved position in 19 moves. It was registered as US Patent number on 29 March 1983 by Ernő Rubik.Rubik's Domino Patent
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References

Hungarian inventions Mechanical puzzle cubes Rubik's Cube {{toy-stub