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On Wed, Feb 15, 2012 at 4:11 PM, Bill Gosper <billgosper@gmail.com <http://gosper.org/webmail/src/compose.php?send_to=billgosper%40gmail.com>> wrote:>> > Neil has just uncovered fq.math.ca/Scanned/6-6/hoggatt.pdf>> > predating my http://mathworld.wolfram.com/SquareDissection.html>> > of a square into ten acute isosceles triangles.>> >>> > Neil also found in a Gardner book a reference to a Monthly paper>> > (June-July 1962, pp550-552) claiming that *any* obtuse triangle can>> > be cut into eight acute isosceles triangles, implying at most nine for>> > dissecting a right isosceles, in contradiction of my round(tan(69))>> > solutions assertion. Has anyone a picture of this dissection?>> > --rwg

SA>Martin Gardner gave the 9 triangle dissection in "The Last Recreations" p253 (but Google books and Amazon wont show me that page) Stuart Anderson [...] This is mysterious. Neil just sent me some screenshots of his electronic edition. P253 is a pure text description of a map-coloring game. Triangular dissections are discussed on pp250 and 252, with illustrations of three dissected squares filling p251, and no mention in the text of nonasecting the 45-45-90 into acute isosceles. Is it likely Neil's edition isn't the latest? --rwg