Print-It-Yourself puzzle are puzzles that you can download from http://oskarvandeventer.nl/Print-It-Yourself/ and print on your own 3D printer. Please print for personal use only.
Curated by: OskarPuzzle (338 videos)
Print it yourself at https://oskarvandeventer.nl/Print-It-Yourself/. Buy at Imperfectible Caltrop is a caltrop design by Robin Houston, see also here (https://sketchfab.com/3d-models/imperfectible-caltrop-97746dc9b08543769029baa15772fc98). Robin described the mathematics of caltrops in his 2026 Bridges paper (https://archive.bridgesmathart.org/2026/bridges2026-165.pdf). A caltrop is a polyhedron where each face has a vertex at the exact opposite side from the origin. This way, the is always a spike (vertex) sticking up, no matter how you drop the caltrop onto the ground. Robin calls a caltrop "perfect", if each vertex has an opposite face as well (same number of faces as vertices). A caltrop is "imperfect", if it has more vertices (spikes) than faces. Most of the imperfect caltrops that Robin found could be easily pruned into perfect caltrops. So he wondered whether an "imperfectible caltrop" exists, that cannot be pruned into a perfect caltrop. This 16-spike caltrop is the first example that he found. Obviously, the next question is what is the lowest number of spikes for an imperfectible caltrop. Copyright (c) 2026, M. Oskar van Deventer. Frequently Asked Question: http://oskarvandeventer.nl/FAQ.html Buy Oskar puzzles at https://www.puzzlemaster.ca/browse/inventors/oskar/ (USA, CA) and https://puzzleguy.store/collections/oskar-van-deventer (EU).