The Altekruse puzzle is named after the grantee of its 1890 patent, though the puzzle is of earlier origin. A classic Altekruse consists of 12 identical pieces. In order to disassemble it, two halves of the puzzle have to be moved in the opposite directions. Using two more of these pieces, the puzzle can be assembled in a different way. By the same principle, other puzzles of this type can be created with 6, 24, 36 and so forth. Despite their size, those bigger puzzles are not considered very difficult, yet they require patience and dexterity to assemble.