50000 rectangles.
After the long description about faux edges and shadows, the next question may be “how do I decide where to put the rectangles”? One sees randomness, but not total randomness in these pictures. There is a hidden pattern, sometimes very well hidden, and sometimes not hidden at all.
I mentioned this many times over the years, and here it is again: I like to visit the boundary between random and not random. It is a wide boundary, and depending on my mood sometimes I land nearer the order side or the chaos side.