Peter Vogel circuit artwork

I found the reference to Peter Vogel through Karl Klomp's website which I will post more on very soon. However I feel that this is worth noting because Peter Vogel's sculptures are complete and interactive audio circuits. In this closeup it appears that the circuits are transistor based oscillators with a resistor feedback. Sounds simple enough, but getting everything connected point to point like that it is a bit of a challenge and an art form in itself. I would imagine that these individual circuits produce simple oscillations and they may also be patched together for cross modulation. There may also be some time based performance factor designed into the circuit, however that is hard for me to say because I have only read the descriptions and not actually seen one in real life. Comments?