* Bill Gosper <billgosper@gmail.com> [Sep 22. 2014 15:55]:

jj>Extra points if you do that gif-ery for the curve http://jjj.de/tmp-ryde/t-shirt-R13-15-hires-cropped.png (L-system at bottom, turns are by 120 degrees). Total curve should be light gray, and the moving part should be 1/13 of the total (so the same shape will appear 13 times, as indicated in the image). ... plus you get a T-shirt! (If you use the image to, well, print one. I got one and it looks quite OK).

Best, jj

That highly symmetric (almost dihedral 6) supersnowflake from three of these in a loop--is that also rep13? Yours?

I assume you mean page 10 of http://jjj.de/tmp-rwg/all-r13-tiles.pdf Here is generation 4 of the same: http://jjj.de/tmp-rwg/r13-15-plus-tile-4.pdf It has rotational 6-symmetry, which (apparently) can only happen for orders of the form 6*k+1. No flip-symmetry (so indeed not D_6 as you mention), and I am fairly sure none of my curves has D_6. Mine? I'd think so. Note I'll be leaving tomorrow morning (that's in 24 hours from now) for http://dimacs.rutgers.edu/Workshops/OEIS/announcement.html and will be away from my mail until 12.10. Best, jj

--rwg _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun