Prototyped a 2x2x2 LED cube on a breadboard

Today the first step toward the 4x4x4 matrix I’ve been wanting to build for a while, was made. Started by watching a video on 2D matrices to understand multiplexing, and adding the third dimension turned out to be surprisingly straightforward: each layer connects to ground through a transistor, each column connects to a power pin, and that setup lets you address LEDs individually or sweep the whole layer at once.
Getting the wiring clean enough on a breadboard that nothing shorted took a few tries, but the prototype is working.
Tomorrow I’m soldering the full 4x4x4 cube and writing the animation logic, hoping it doesn’t immediately go up in smoke.