Print-It-Yourself Puzzles

Currently Playing: Satisfiable Puzzle - Is this a puzzle or more a fidget?

Print it yourself at https://oskarvandeventer.nl/Print-It-Yourself/. Buy at https://i.materialise.com/en/shop/item/satisfiable-puzzle Satisfiable Puzzle has ten buttons. The goal is to push seven buttons down. However, when you push a button down other button(s) may pop up. Magnets keep the buttons up or down. Seven lengths of ball chain engage with the buttons. Three buttons rest on each length of ball chain. The length is chosen such that when two of the three are pushed down, the third one pops up. It is easy to push five or even six buttons down, but the seventh has a unique solution. Once you have solved the puzzle, you can randomly swap the buttons and try again. It is a very tactile and pleasing puzzle. The puzzle was named after the Boolean satisfiability problem ( https://en.wikipedia.org/wiki/Boolean_satisfiability_problem ). This is a classic problem, where the challenge is to find the binary input values for which a given Boolean expression results in "true". The problem is NP-complete, which means that it is hard to solve, but easy to verify that a solution was found. This is also true for the puzzle, where one can easily verify that seven buttons are down. Copyright (c) 2025, M. Oskar van Deventer. Frequently Asked Question: http://oskarvandeventer.nl/FAQ.html Buy mass-produced Oskar puzzles at https://www.puzzlemaster.ca/browse/inventors/oskar/ (USA, CA) and https://www.sloyd.fi/brain-teasers/inventors-designers/oskar-van-deventer (EU) Buy exclusive 3D-printed Oskar puzzles at https://i.materialise.com/shop/designer/oskarpuzzle, https://www.chewiescustompuzzles.com/puzzleshop/oskars-puzzles