Hilbert Curve on EC, suggested by Igor:
https://everycircuit.com/circuit/5828091149811712
achieved this using 'gray code' with a form of iteration
it has some noise due to propagation delays, so still working out the kinks. had to add low pass filters to reduce the jitters
fixed kink-less version:
https://everycircuit.com/circuit/4796901781929984
