Diabolical cube seven and nine pieces respectively. However, writes that the diabolical cube appears to be the oldest puzzle of this type, first appearing in an 1893 book "Puzzles Old and New" by Professor Hoffmann (Angelo Lewis). Because all of the pieces have only a single layer of cubes, their shape is unchanged by a mirror reflection, so a mirror reflection of a solution produces either the same solution or another valid solution. The puzzle has 13 different solutions, if mirrored pairs of solutions are not counted as being distinct from each other. Diabolical cube The diabolical cube is a three-dimensional dissection
Unit cube Unit cube A unit cube, more formally a cube of side 1, is a cube whose sides are 1 unit long. The volume of a 3-dimensional unit cube is 1 cubic unit, and its total surface area is 6 square units. The term "unit cube" or unit hypercube is also used for hypercubes, or "cubes" in "n"-dimensional spaces, for values of "n" other than 3 and edge length 1. Sometimes the term "unit cube" refers in specific to the set [0, 1] of all "n"-tuples of numbers in the interval [0, 1]. The length of the longest diagonal of a