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
Hilbert cube Hilbert cube In mathematics, the Hilbert cube, named after David Hilbert, is a topological space that provides an instructive example of some ideas in topology. Furthermore, many interesting topological spaces can be embedded in the Hilbert cube; that is, can be viewed as subspaces of the Hilbert cube (see below). The Hilbert cube is best defined as the topological product of the intervals [0, 1/"n"] for "n" = 1, 2, 3, 4, ... That is, it is a cuboid of countably infinite dimension, where the lengths of the edges in each orthogonal direction form the sequence formula_1. The Hilbert cube