input colorbrewer-rgb
vardef pinwheel(expr level, a, b, c, s) =
 if level = 0:
   fill a--b--c--cycle withcolor s;
   draw a--b--c--cycle;
 else:
   save d, e, f, g; pair d, e, f, g;
   d = 1/2[a,b]; e = 1/5[c,b]; f = 1/2[a,e]; g = 1/2[b,e];
   pinwheel(level - 1, f, d, e, Blues 9 2);
   pinwheel(level - 1, f, d, a, Blues 9 3);
   pinwheel(level - 1, e, a, c, Blues 9 4);
   pinwheel(level - 1, g, e, d, Blues 9 5);
   pinwheel(level - 1, g, b, d, Blues 9 6);
 fi
enddef;