My latest is a bit more complicated. I added blinky lights.
I got the circuit diagram from
here, blew the dust off of my Electrical Engineering class equipment, and made several trips to Radio Shack. CAT5 cable conveniently has enough wires for a ground, 3 pairs of alternating blinkers, and one always-on light, so I put an ethernet socket in the project enclosure.
Here are the resulting electronics, with the enclosure open and closed.