Comments on: The Making of The Pentultimate

The Making of The Pentultimate

Wolfdog — Mon, 05 May 2008 15:18:53 -0800

The Making of The Pentultimate - a beautifully obsessive documentation of modeling, casting, and assembling a "deep cut vertex turning icosahedron", or put another way, the path from 820 fiddly little bits to an elegant 32-piece mechanical puzzle.

By: Wolfdog

Wolfdog — Mon, 05 May 2008 15:22:27 -0800

I would call it face-turning, not vertex-turning, but I would also have lost most of the bits so he can call it whatever he wants.

By: quin

quin — Mon, 05 May 2008 15:26:00 -0800

The end result. Which I just noticed is linked here on one of the last pages. If penultimate is second from last, is pentultimate 5th from the end?

By: rongorongo

rongorongo — Mon, 05 May 2008 15:33:33 -0800

I like the way the guy in the video has already resorted to bandaging the ends of his fingers.

By: blacklite

blacklite — Mon, 05 May 2008 15:48:20 -0800

So, this is neat and all, and very nice, but how the hell do you get all of that material, a computer-guided mill, and enough time to design that and build it? I guess the builder must be at some university somewhere, but damn.

By: GuyZero

GuyZero — Mon, 05 May 2008 16:16:47 -0800

enough time to design that and build it I heard an interesting comment on the radio about this the other day. Some TV person asked some interweb pundit where people got the time to edit Wikipedia. His retort? You have no right to ask anyone where they get the time to do anything - if everyone stopped watching TV tomorrow and did something productive instead we could build pretty much anything. Americans collectively watch about 250 billion hours of TV a year. Which is about 2 hours per day per person. I bet he could do all that in 2 hours a day.

By: hincandenza

hincandenza — Mon, 05 May 2008 16:21:25 -0800

This is amazing- there is a whole community of people who make custom, Rubiks-on-steroids type puzzles, and apparently this particular icosahedron model is something of a titanic achievement. Here's the thread on twistypuzzles.com where the creator announces it (apparently many people have sketched and discussed such a thing, but he's the first to actually make it work, and quite beautifully too). Two things stood out to me: 1) First, several of the responders have in their sigs links to their own puzzle-making pages where they've crafted custom puzzles as well. I had no idea people where crafting these sorts of things, beautifully working hand-made puzzles. 2) Second, the original post was made at Thu Mar 20, 2008 1:31 am. Noah, who's apparently quite the math whiz/puzzle solver on those forums, then posted not 2 hours later at 3:27 am, said "Have you scrambled it yet? I wrote a solution for it already if you need one. It might not be optimal, but it works.". Wow! I guess given that some other puzzle makers on that forum in their sites mention having a "Master's degree in Algebraic Graph Theory, and soon PhD in Control Systems Engineering", these people are the savants of the math and crafting of puzzles.

By: Carmody'sPrize

Carmody'sPrize — Mon, 05 May 2008 16:26:59 -0800

I second that. I've done some prototyping like this and it isn't all that difficult. The digital based fab is pretty straight ahead. The RTV molding requires a much higher level of physical craft. What hasn't been mentioned is the cost. Those materials aren't cheap. Neither is the equipment. The website would be a lot more interesting to me if he accounted for the time and money associated with each step.

By: Blazecock Pileon

Blazecock Pileon — Mon, 05 May 2008 16:29:07 -0800

I hear Pinhead has a whole box of those.

By: Wolfdog

Wolfdog — Mon, 05 May 2008 16:47:52 -0800

posted not 2 hours later Well, the puzzle was described years ago and has been available to play with in virtual form for a long time, so that solution probably wasn't cooked up in the 2 hours after the announcement of the working physical model.

By: blacklite

blacklite — Mon, 05 May 2008 16:49:09 -0800

You have no right to ask anyone where they get the time to do anything That was Clay Shirky, talking about "cognitive surplus". (I don't know who Clay Shirky is, but he sure is pushing that book.) I was talking about money and materials and opportunity, not just time.

By: DU

DU — Mon, 05 May 2008 17:08:35 -0800

1) Whoa. 2) I want... 3) Whoa. 4) ...one.

By: Wolfdog

Wolfdog — Mon, 05 May 2008 17:18:04 -0800

DU - Katsuhiko Okamoto's small run of 4-layer Master Pyraminxes sold for somewhere $600-$1000 a piece, as I recall, though I can't seem to document that at the moment. I think Jason (the pentultimate guy) might have similar goals in mind.

By: furtive

furtive — Mon, 05 May 2008 18:09:20 -0800

0.13mm! Hand me your calipers so I can pinch you with them!

By: piers

piers — Tue, 06 May 2008 00:47:08 -0800

Not to nitpick, but that shape is actually a dodecahedron (pentagonal faces). An icosahedron would have 20 triangular faces. It sounds like he had the idea for an icosahedron puzzle but went with a dodecahedron instead. Now, if it had been a pie-cosahedron that would have really been something.

By: jpdoane

jpdoane — Tue, 06 May 2008 11:44:50 -0800

Why does he need so many layers for the interlocking mechanism? It seems overly complicated, and I'm not surprised that he has trouble turning it

By: Wolfdog

Wolfdog — Tue, 06 May 2008 13:45:50 -0800

I've honestly not entirely digested how the mechanism works - and more than the molding and all the physical processes it is the design that impresses me. But it looks like each of the twelve faces causes motion at a distinct level that it "owns", and the pattern of interlocking on that level makes the other related faces turn simultaneously at the same time. So each level's tabs encode the motions for one kind of face twist.

By: Tube

Tube — Wed, 07 May 2008 01:15:49 -0800

The model splits and rotates about its equator, thus it is not a dodecahedron. The "Pentultimate" is not a regular solid but looks to be a stellation of the icosidodecahedron.

By: Wolfdog

Wolfdog — Wed, 07 May 2008 05:01:45 -0800

Yes, it's a dodecahedron, it just has cuts. Might as well say Rubik's cube isn't a cube because of the cuts.

By: Tube

Tube — Wed, 07 May 2008 20:23:56 -0800

Sectioning a cube creates new little squares on the faces. But sectioning a dodecahedron creates new little triangles, thus turning a dodecahedron into an icosidodecahedron, or in the case of the Pentultimate, a partially stellated icosidodecahedron.