Rupert's Snub Cube and other Math Holes
Why Hacker News recommends it
HN commenters cite it as the accessible, entertaining deep dive on Rupert and Nopert polyhedra whenever the related math results or the Noperthedron paper come up, and as a showcase of Tom7's humor and technical depth.
Recommended by 5 people across 3 different months, 2025 to 2026.
What it is
Tom 7 (suckerpinch) presents an 80-minute crossover episode about Rupert's property: whether a polyhedron can pass through a hole in a copy of itself. He searches for a "Nopert", a convex shape that cannot, covering the snub cube, the triakis tetrahedron and related solids, with code and a paper on his project site.
Cited in 1 Wikipedia article, including Tom Murphy VII.
What people said
Strong rec pinkmuffinere · 2025-10 · Hacker News · on “First convex polyhedron found that can't pass through itself”
Tom7 is one of my favorite people, he is hilarious, has an amazing technical depth, and so much whimsy to go along with it. I'll proselytize for him all day! relevant video: [this video] less relevant, but I think my favorite: [LINK]
Strong rec Rendello · 2026-09 · Hacker News · on “Paper Models of Polyhedra”
I'm not deep into geometry, but one of my favourite web apps / UI designs is the Polyhedra Viewer by Nat Alison [1][2], which shows relations, properties, and transformations in a very natural way. Tom7's video on polyhedra properties [3] is also great, and taught me about the best Unicode characters (sic) [4]: ︘ U+FE18 Presentation Form For Vertical Right White Lenticular Brakcet 1. [LINK] 2. [LINK] 3. [this video] 4. [LINK]
Recommends king_geedorah · 2025-10 · Hacker News · on “First convex polyhedron found that can't pass through itself”
Rather interesting solution to the problem. You can't test every possibility, so you pick one and get to rule out a bunch of other ones in the same region provided you can determine some other quality of that (non) solution. I watched a pretty neat video[0] on the topic of ruperts / noperts a few weeks ago, which is a rather fun coincidence ahead of this advancement. [0] [this video]
Recommends mrguyorama · 2025-10 · Hacker News · on “First convex polyhedron found that can't pass through itself”
Fans of "Tom7" should be very recently familiar with this! He released a video about the Ruperts problems and his attempt to find a Nopert on just Sept 16th! [this video] With this and the Knotting conjecture being disproven, there are have some really interesting math developments just recently! Tom regularly releases wonderful videos to go with SIGBOVIK papers about fun and interesting topics, or even just interesting narratives of personal projects. He has that weird kind of computer comedy that you also get from like Foone, the kind where making computers do weird things that don't make sense is fun, the kind where a waterproof RJ45 to HDMI adapter (passive) tickles that odd part of your brai
Recommends fsckboy · 2025-12 · Hacker News · on “Noperthedron is not Rupert (can't fit through itself) [video]”
this video is new and an easy watch, based on this paper which has been on here before [LINK] and here's the Tom7 video he recommends if you want to go deeper [this video]