I have re-run the evolution of Darwin’s image using 128 circles four time now. This graph shows the decrease in distance between the evolved and target image over time for each of the runs (the darkest line is the first run). The initial distance value varies quite a lot between the four different runs, but by about 1000 generations, the values are approximately the same. I plan to compare this rate of evolution with the rate of evolution when there are more circles or a different rate of mutations.
Here are a selection of images from five time points in each of the four runs of evolution. The numbers along the left and right are the d values for the first and last image in each run.