I posted pictures of my project (can't find them at the moment) on a car forum that I frequented and many members asked me to make one for them. I designed the printed circuit board, had them made and soldered all the stuff up to make hundreds of finished products ready to install in your car. There were 3 versions through out their productions years.
The first one scanned left to right only.
Version 2 had a speed control and a panic switch to make it function as a regular brake light if a cop was behind you.
Version 3 had several programmed patterns. There was a control module in the cabin to allow you to change the patern and see a display of what the actual brake light pastern was doing in the rear.
Here is the control box board with surface mount components
This is the PCB that goes into the brake light housing. Please note the 4 prong flat LEDs. These are the same high powered LEDs as used by emergency vehicles and stop lights. These were all powered by transistors in the picture above.
This was the version 3 kit ready to go
This was the mock up for the control box
I designed the PCBs (printed circuit boards) so I could get two LED light panels and 2 controller boards on one board to help keep the production costs down.
I wasn't sure if this belongs in the garage or tinkers table, but I wanted to share this bit of my history with y'all.