MathPuzzle.com

Material added 27 June 2020

NPR Puzzle The NPR Puzzle is mine this week. Think of a 5-letter animal. Remove the middle letter, and two opposites remain. What animal is it? Heesch 4 Craig S. Kaplan‎: It seems appropriate to spend some of this quarantine computing coronas! Here's the smallest polyiamond with Heesch number 4, a 20-iamond. Anagram We're all in this together
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We are still here tonight. Puzzle Fun Magazine A new issue of Puzzle Fun is out. Proofs From The BOOK Many titles like Proofs From The BOOK are currently available free from Springer. PsiQuad 3-colorable Stan Wagon has shown that my Psiquad tiling is likely 3-colorable. A4 Paper Here's one of those solutions that's so mathematically perfect that I can't believe that I'm the one that found it. All rectangles are similar to the outer rectangle, which has area 200. Theoretically, 50, 64, 72, 81, 98, 100, 121, 128, 144 can be added to get a similar rectangle with area 1058. I picked this set because there were lots of potential edge-matches, but I got forced to a solution where no edges matched. Didrafters and Taco Chips George Sicherman: The below shapes are the 13 didrafters. Arrange 8 of the 13 didrafters to make a solid rectangle. Then make nine convex shapes. Then add a few more pieces for the Taco Chips puzzles. Food Menu I found this food menu amusing. Foster 084 A Graph While at a meeting for making nice graph embeddings out of graphs that looked lousy, I made what is likely the first nice embedding for the Foster 084A graph. Venn 7 Venn 7 from Andreas Gammel. Extraordinary Conics With five lines/points, find the conic. Interstellar Blackboards The Blackboards of Kip Thorne in the background of Interstellar. 1D CA Carpet This 2D fractal can be made with a 1D Diagonal CA. Unholey Deciamonds Patrick Mark Hamlyn‎: The 444 unholey deciamonds in 37 congruent shapes. Took about 24 hours to develop piece tilability data for the BFS for this shape, and 43 minutes to tile the 37 shapes using that data. Graceful Graphs The first is the unique minimal heptic graceful graph. The next is a minimal octic graceful grace. The third is a graceful rook grid with all differences 1 to 48. Conway Knot Problem Lisa Piccirillo has solved the Conway Knot Problem. Safety First Things are getting safer here in Illinois ever since we went hardcore on it back in March. Conway, Berlekamp, Guy Soon after Conway, Berlekamp, and Guy signed this for me, Conway hunting me down. "Ed, we need to borrow our books!" So I handed them over. They met with A.K.Peters and Tom Rodgers to arrange for the second edition 4-volume set of Winning Ways. So long old friends. Remembering John Conway. Remembering Richard Guy and John Conway.