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Article #2513Re: Alternate cover shape [SPOILER]
From: Dan Blum
Date: Tue, 05 Jan 1993 22:43
Date: Tue, 05 Jan 1993 22:43
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1555 bytes
Timothy Vaughan (tvaughan@buphyk.bu.edu) wrote: > I just thought of a non-circular shape that won't fall through. > I don't know what it is called, but it is the shape of the rotor > in a Wankel engine. It has constant diameter, although not > constant radius. It could be described nonrigorously as a "rounded > triangle." I will try to derive the equation for it. > Tim I think that this is called a Delourede triangle, although I won't swear to it. There are an infinite number of other constant-diameter figures, any of which should make a suitable cover. Martin Gardner wrote a column about them - I can't remember which collection it's in. -- _____________________________________________________________________ Dan Blum Institute for the Learning Sciences Room 327 blum@ils.nwu.edu 1890 Maple Ave., Evanston, IL 60201 708-467-2306 "It's nothing, honey - the dog's learning how to juggle." _____________________________________________________________________
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Newsgroups: rec.puzzles Path: arc1-ca.pugleaf.net!sparky!uunet!zaphod.mps.ohio-state.edu!news.acns.nwu.edu!news.ils.nwu.edu!medici.ils.nwu.edu!blum From: blum@medici.ils.nwu.edu (Dan Blum) Subject: Re: Alternate cover shape [SPOILER] Message-ID: <1993Jan5.224311.8293@ils.nwu.edu> Sender: usenet@ils.nwu.edu (Mr. usenet) Nntp-Posting-Host: medici.ils.nwu.edu Reply-To: blum@ils.nwu.edu Organization: The Institute for the Learning Sciences X-Newsreader: TIN [version 1.1 PL8] References: <106207@bu.edu> Date: Tue, 5 Jan 1993 22:43:11 GMT Lines: 20