My one quibble with the comment I linked is about asymptotics. By the Prime Number Theorem, asymptotically, the density of black squares should approach zero and the density of red squares should approach 100% (including among the left diagonal which is entirely black in the displayed window, and including losing the regular appearance of rows that are entirely black except for their last cell. These black line patterns in the displayed window are both small number phenomena caused by (1 - 1/ln(R))^100 being nearly zero for small R, which stops and then goes the other way for large R.)