ZX Spectrum didn't have joystick interface. So Poland had a cottage industry to build one as cheap as possible. The best hack was to construct logic gate using

ZX Spectrum didn't have joystick interface. So Poland had a cottage industry to build one as cheap as possible. The best hack was to construct logic gate using germanium transistors to avoid expensive gates with 3 state output. Connecting a printer required building yourself a Centronics interface and writing a driver for it. I recall some people managed to build floppy disk controller and connect 5 1/4 drive.