It works right from the beginning. Testing after more or less each step paid off.
Many basic op amp circuits are used in this sculpture: integrators and differentiators in the chaotic circuits, buffers and amplifiers in the signal conditioning, a very dirty triangle signal generator, a peak detector, building the difference between signals and converting analog to PWM. Best practices were not always applied. But in this project it's not about signal quality in the first place. The idea was to use the op amps to make the lighthouse blink in a non-repetitive way. This would also be possible with a micro controller and a few lines of code - but much less fun!