How about a Hadamard Tiling! Here each tile is a Hadamard matrix that has been superimposed on itself 4 times, but each time rotated by 90 degrees. Kind of curious how the matrix e has only two values, this is not true for some other orders I have tried. . start Rot90(m); /* from Rick's blog */ return( T(m[,ncol(m):1]) ); finish; a = hadamard(36); b = Rot90(a); c = Rot90(b); d = Rot90(c); e = a + b + c + d; t = repeat( e[2:35, 2:35], 12, 12); /* strip the borders and tile */ ods graphics / width=600px height=600px; run HeatmapDisc(t) colorramp = palette("PIYG", 4) displayoutlines = 0;