Since the PCBs are meant to be wearables, I wanted to come up with a nicer shapes. So I designed a Heart shaped one.

The idea is basically the same as for the pizza. It's a ring oscillator consisting of an uneven number (in this case 13) of inverters. This one is also powered by a CR2032.

Two main differences are that for the sake of space on the PCB I use resistor array packages as current limiting resistors for the LEDS and dual packaged MOSFETs. Also there are two holes in to top to add small wire loops.