I just published the unobfuscated version of the 1989 IOCCC Best Game entry, Tetris™. See the original author’s, John Tromp, home page for the game for details. But suffice it to say, this is an extremely bare bones version of the classic game and very similar to the BSD games’ version.
Actually, this similarity in board layout, key combinations and feel led me to do some archaeological digging. I dowloaded the classic BSD games collection and, after having called GNU Indent on the obfuscated code, I started noticing such extreme similarities that just could not be coincidental. The layout and constructs of the code are virtually the same, so I can only conclude that they must share the same ancestor. Maybe this code is that ancestor, considering that the BSD Tetris is copyrighted in 1992 and this version stems from 1989, it is maybe not a completly illogical conclusion.
See for yourself.