Personal nostalgia!
This dates from 1996 and was the first reasonably serious program I ever wrote. Lots of hours in books and bouncing code off of a good friend who helped me get started. Some code in Swedish.
Runs OK in DOSbox. tetris.exe is commited to the repo; I haven't even bothered to dig up some working compiler environment for this. IIRC, some version of Borland C++ was used.