Using piloted pneumatic valves as logic gates blew my mind. If you are looking for strangeness, the 1990's to early 2000's microcontrollers had I/O ports, but

Using piloted pneumatic valves as logic gates blew my mind. If you are looking for strangeness, the 1990's to early 2000's microcontrollers had I/O ports, but every single I/O port was different. None of them had a standard so that we could (for example) plug in a 10-pin header and connect the same peripheral to any of the I/O ports on a single microcontroller, much less any microcontroller they made in a family of microcontrollers.