A simple algorithm results in unpredictable and complex patterns when iterated multiple times.
Circles are generated at random points on the canvas, of random diameters (within limits).
New circles are drawn wherever two circles overlap, their diameter calculated such that they touch the two parent circles.
By the 3rd generation, the pattern has evolved beyond any initial predictions.
Some of the visuals are show the 3rd or 4th gen circles, some show centre-to-centre lines of every parent pair, and some show both.
The essence of generative art is that you only set up rules, and let them interplay to give you something you could not have predicted.