I'm impressed by the method of cutting copper foil to produce circuitry. Saves you the acid and/or ordering from Shenzhen.
From TFA.
This was surplus sheet. Doesn't scale, but fits the reduce/reuse/recycle model well, 2nd mode.
I've done freeform electronics before, using wiring that was mainly the snipped-off legs of through hole resistors. I guess if you were fancy you could buy some bus wire. The assemblies are horrific to look at, and I love them.