The ubiquitous Tetris is a puzzle game where players manipulate a random sequence of falling, four-block to create a horizontal line of blocks without gaps. Versions for desktop computers appeared in the 1980s, and the first handheld edition for the Nintendo Game Boy debuted in 1989.

The Game Boy version proved wildly successful, selling over 35 million units, according to the . EA Mobile released and iPod touch in 2008.

EA Mobile, which licenses Tetris from Blue Planet Software, says the game is available on some 64,000 handsets in 60 countries, according to an Associated Press .

What makes Tetris so appealing? Is it the shallow learning curve? The lack of gratuitous sex and violence? (Yeah, right.) Or perhaps there's something strangely spiritual about the game that few of us comprehend.

This brief prayer from the says it best: