You'd use two current-limiting resistors per LED as legs, rolled up wire or component leads as antennae, and ordinary or blinking 3/5/10mm LEDs for show. The back side has a CR2032 battery holder for power. The hardwear.io folks have manufactured the badges and my understanding is that they were well received.
I adapted the design for my own, and manufactured a few as well.
There are two 'solder-blob' jumpers that allow powering the buggy through the eyes (instead of from the battery, never both), which can also function as holes for attaching to a lanyard or worn as a necklace ;)
As usual, this board is open source hardware. Get the latest version of the board at the Boldport repo.
Until next time, 'buggy' says farewell