4-bit mechanical binary counter

This is a Principia recreation of HottuB's 4-bit binary counter level from Apparatus.

It uses some Principia electronics, such as a sequencer and the debugger for showing the state of bits, but otherwise works in a rather mechanical manner like the Apparatus version does.

While the original Apparatus level is lost to time, it can be seen in the Community Level Montage & Christmas Music video by Bithack, around 1:26.