It's most likely you've come to play Tetris through many hours of button-prodding on the Nintendo Game Boy. But the real hero is inventor Alexey Pajitnov, a Russian genius with a fixation for puzzles and an affinity with beards [brains and style!]. Here is a tribute recreation from Paul Neave.
Here's how you play. Shaped blocks (called tetrominoes by the way) fall into a pit where you need to arrange them so they form a complete horizontal line. Once a line without gaps is created, it disappears and the blocks above fall down. The more lines you create simultaneously, the more you score.
Remember to take a break every few hours or your eyes will actually start seeing everything square (I tell you this from experience!).
Move - arrow keys Pause game – P
Fast drop – down key Quit game – Q
Rotate clockwise – up key or X Rotate c/clockwise – Z