Many, many times have friends shared a circuit board nail design with me, requesting that I replicate it. Not only is it cool, but also related to my degree which means that I've left it until I found something I was happy with. I didn't want to start painting golden lines unless I knew what it actually did, would it be an actual circuit. I finally got around to it, but decided to keep it straightforward.
On my left hand, I started off with three filters: band-pass, high-pass and low-pass. With the ring finger and pinky not being very big it seemed easier to show diods in parallel/series.
Bode Plots). I considered doing that for my right hand, but decided I was too lazy and took an easy way out instead. In the picture you can see the schematic symbol for a capacitor, inductor, resistor and a battery. I decided to spend a little more time for the thumb and made a basic op-amp circuit.
Op-amps and filters are pretty neat, but I've barely touched them since second year. Well, filters are hard to avoid but op-amps easily disappear into bigger "black boxes". However, you should look them up. They are cool.