However, it was obtained with the applet below (# Rows 64, # Colors 64, Operation x·y AND (x+y) and Colors Reversed as the low right portion of the Square.)
The applet draws a square or triangular array of dots whose color is defined through simple arithmetic and bitwise operations. x and y coordinates are counted from the upper left corner of the array. (The triangular array is just a sheared version of the lower left half of the square.) They then are combined by the selected Operation. The result is taken Modulo the number of colors. Or, as an alternative, in the Binary mode all non-zero results are made to correspond to a single quantity. The finite result becomes an index into an array of gray shades.
Note how much the low right portion of the original display (# Rows 32, # Colors 31, Operation x OR y, and Colors Reversed unchecked) resembles the fractal structure of the Sierpinski gasket or that of Pascal's triangle in modular arithmetic.