Back in the early 90s I got my first car and decided I wanted to replace some of the 194 incandescent bulbs with LEDs. I was a big LED fiend and had a full bag of red and green ones. I picked up some yellow ones and got so far as to build a replacement for my tail lights which I never installed. I also built a third brake light/second blinker using soda straws, red LEDs, and phone station wire.
These were my first attempts at replacement dash and marker lights. Well before I understood the calculations for connecting 3VDC LEDs to a 12VDC system -- notice the burned resistor