He used a 555 timer that outputs a clock to the LEDs on the biz card, and placing a nine-volt battery on the terminals sets off the mini light show. See for yourself in the video below.

Instead of going with a microcontroller he built the circuit around a 555 timer. ... 555 Push Button Toggle ” ... Each pixel is basically an integrator for light.

The Hackaday comments section has become infamous for a recurring theme that goes something like “I don’t know why they used an Arduino, they could have done it with a 555 timer!”… ...