Tetris (1986)

This puzzle, a remake of an old Russian game called Pentaminos, by the game designer Alexey Pazhitnov, is possibly the most "cloned" Shareware arcade game in history, this addictive arcade game from Russia first appeared on Shareware BBSs in 1986 for the IBM PC. Clones and enhanced versions have been released for virtually every platform and are still being made today.

The basic idea is to efficiently pack an empty box with various shaped blocks (6 in this original version) that fall down into it. Fitting them together to complete lines (rows), use your keyboard to rotate, move and drop the blocks into position as they fall. When you succeed in completing a line (all empty spaces filled in it), the line (or row) disappears, making room for more. The faster you go, the higher your score. The speed in which the blocks appear and descend increases when you reach higher levels. The shapes of the blocks are random, so the game is different each time you play.