tromp 5 days ago

The bottom of my home page has this as a PostScript signature:

    %!PS                           % -John Tromp http://tromp.github.io/
    /t{dup 1 sub gsave dup 0 gt{[.4 .2 -.2 .4 .4 .2]concat t currentgray
    .8 mul .2 add setgray -1 1 scale t -1 2 translate t 1 -1 scale t[0 1
    1 0 0 2]concat t pop}{0 moveto 1 0 lineto 0 2 lineto closepath clip
    fill}ifelse grestore}def 10 10 translate 600 600 scale 5 t showpage
which outputs this pinwheel tiling https://tromp.github.io/img/pinwheel.pdf
Leptonmaniac a day ago

Super interesting! So if I understand correctly, all you need to do to have this in your home is gather a bunch of 1:2 tiles, cut them along the diagonal, and assemble them as shown? Awesome

xvedejas 2 days ago

How could one prove this is aperiodic? I'm guessing maybe you can prove that some or most of the triangles have globally unique rotations regardless of N?