Date: 3 September 1980 2328-EDT (Wednesday) From: Dan Hoey at CMU-10A To: Cube-Lovers (and Hackers) at MIT-MC Subject: Addictiveness/Disassembly/Taxonomy/Lubrication/Spoilers Message-Id: <03Sep80 232808 DH51@CMU-10A> Hello. I saw the notice announcing the formation of this list a couple months ago, and decided that it was one of those things I could forgo -- until I got my hands on a physical cube. It was an immediate necessity to own one. I bought an Ideal brand cube, which, I understand, is of the species C. Americanus in spite of its "Made in Hungary" label. I had owned the cube less than ten minutes before a facie cover fell off, without the aid of chemical additives. This was not very destructive; just about any gummy material (I used gluestick) suffices to hold it on. However, the screw head revealed by this unusual transformation leads to a new method for disassembly. Unscrewing does not stress the cube as does prying, and probably avoids the deleterious side-effects observed by Greenberg (16 Aug 1453). This method is not without its hazards, however. It is EXTREMELY easy to strip the threads on the plastic X that holds the cube together. I have paper shims in the two threads I stripped and they seem to suffice. Still, it is probably better just to loosen the screw until the cube comes apart with gentle prying. There is at least one good reason for taking a screwdriver to the cube. Mine had been assembled with several of the screws so tight that the springs were completely compressed. Due to mfg inaccuracies in the cubies, this made the cube difficult to twist. By prying each of the facies off with a fingernail I was able to correct the tension. Jim Saxe's cube, putatively of the same species but purchased in a different store at 80% the price, has facies which seem impervious to this prying even after disassembly a la Greenberg (17 Jul 2118). Jim and I exhausted our fingernails to no avail, and careful prying with a knife was unsuccessful. Additionally, this cube has a strong tendency to jam, due either to its uncorrectable looseness or to its edge cubies, which have oversized tongues with extremely sharp edges. The differences lead us to believe that our cubes may belong to different species in spite of their outward similarity. I am amazed that anyone would put molybdenum disulfide on their cube. Isn't that stuff poisonous? Graphite works well but is messy if you overdo it. Silicone lubricant was mentioned by Zimmerman (25 Aug 0907) -- has anyone any experience with this? Merrick Furst recommends soap. For anyone who cubes in public, the only word for LACK of fear that someone will F your cube is Cubemeistership. I made a mistake in taking the cube to one session of a recent conference. The sequence 4(Borrow)4(Borrow') appeared to have an entropic effect on the cube and a negative effect on the transfer of information. SPOILER WARNING: I have one transform which I haven't seen here, and which I find useful: an 8-qtw move to permute three corners of a face. Specifically, for {fdl flu fur -> ufl rfu lfd} do . Mnemonically, you move a socket back and forth between flu/fdl with the f/F transforms, alternating with moving one of the three pointies (cornies?) to be permuted into the socket. Why it works is a mystery to me, but it's useful. Another, which should be obvious but improves Landauer's (27 Aug 0128) C7, is the cw monotwist {flu -> luf in u-face} =. Then {flu fur -> luf rfu} is = taking 16qtw instead of 60 (assuming =, =). All for now. -- Dan