From munafo@vgi.com Mon Jul 24 19:11:44 1995 Return-Path: Received: from vgi.com (hoss.vgi.com) by life.ai.mit.edu (4.1/AI-4.10) for /com/archive/cube-lovers id AA02144; Mon, 24 Jul 95 19:11:44 EDT Received: from frank.vgi.com ([1.0.2.139]) by vgi.com (4.1/SMI-4.1) id AA00606; Mon, 24 Jul 95 19:11:41 EDT Received: by frank.vgi.com (1.38.193.4/SMI-4.1) id AA11325; Mon, 24 Jul 1995 19:12:00 -0400 Date: Mon, 24 Jul 1995 19:11:50 -0400 (EDT) From: Robert Munafo X-Sender: munafo@frank To: CUBE-LOVERS List , Nichael Cramer Subject: Shallow-cut dodecahedron, and Re: Little keychain cubes In-Reply-To: <9507242021.AA21879@life.ai.mit.edu> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII I have also noticed that the discussion on the "shallow-cut dodecahedron" a.k.a. Hungarian "super nova" has come and gone a couple times. What I'm talking about is a puzzle that looks like a Platonic dodecahedron (12 pentagonal faces) cut like +''':'''''':'''+ +'''':'''':''''+ : : : : : : : : .:...:........:...:. .' .' : `. : : : : :'''':'''''''':'''': : : : : : : : : .' .' `. `. .' .' `. `. :. : : .: or :`. : : .': : `: :' : : `: :' : + .'`. .'`. + + .''. .'`. + `.: `. .' :.' `. : `. .' : .' `. `. .' .' `. `. .' .' `. `..' .' `. :: .' `. .'`. .' `. .' `. .' `: :' `. .' `..' `..' and manipulated by turning a face 72 degrees around its axis of 5-fold rotational symmetry (an operation that moves 5 edge pieces and 5 corner pieces). I'd like to cast the parts for one of these as well. It seems that the only difficult part would be the 12-pointed "spindle" that holds all the center pieces. It has to be strong, rigid and perfectly aligned. The easiest thing would be to screw bolts into a 12-sided die (of the D&D variety) but I think the alignment would be too poor. On Mon, 24 Jul 1995, Nichael Cramer wrote: > >Does anyone know how I could get more of those little 25-cm 3x3x3 cubes that > > 25-Cm!?! Damn son, you must have a helluva lot of keys! ;-) Oh, yes of course I meant to say 25 mm, not 25 cm. <-: Of course, a 25-cm cube would be fun to have, too. I imagine it would be about a 25x25x25, which would have about 7.3 * 10^2328 combinations (even without considering face centers). God's Number would be well over 1000, and even "Pons Asinorum" would be a major effort at 150 QTW. Since it's an odd-order cube, it could be built by the simplistic "sextapole magnet" method (each cubie has a north pole on its inward-pointing faces and a south pole on its outward-pointing faces, except for the cubiess on the three central planes which could be hollow steel) [-8 > >I'd like to get a bunch of small cubes so I can keep a bunch of cubes > >in different configurations. > > Probably a dumb idea, but if they're going to stay fixed, couldn't you just > paint some up? Sort of a minimalist approach... but I have a notebook for recording patterns. Most of what I want to do involves having a bunch of cubes in the same pattern, then performing different transformations on each one and comparing the results. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - More software projects have gone awry for lack of calendar time than for all other causes combined. [Fred Brooks, _The Mythical Man-Month_, p. 14 (and again on p. 26)] - - - - Robert P Munafo - - - munafo@vgi.com - - - +1.617.276.8960 - - -