Tetris: 30 years old and still addictive

This Friday marks the 30th anniversary of a game that, as you are reading this, thousands of people will still be playing, perhaps cursing in frustration at their decades-long addiction. The game is Tetris and it remains the biggest-selling computer game of all time, with more than 150 million copies purchased since its release on June 6, 1984, across nearly every console and platform.

To put that figure into perspective, that's 50 million copies more than its nearest rival, Wii Sports (for the Nintendo Wii). But it's not only a matter of numbers - Tetris' impact on the gaming world cannot be understated, and its influence is arguably greater than that of any release before or after, Pac-Man, Mario, Doom and Grand Theft Auto among them.

The Tetris phenomenon can largely be boiled down to the most important factor in any video game: gameplay. In Tetris, the concept is simple - but difficult to explain on paper. The game involves more than just playing with virtual building blocks: Tetris provides a playing field where various geometric shapes slowly drop vertically. The object is to rotate them to fit together into horizontal lines. When a solid line is created, it disappears, and the lines above it fall down a level.

The game never "ends" and there's never a winner, only those who gain the most points. So how could something so straightforward, so seemingly ordinary, become such a phenomenon? Henk Rogers, managing director of the Tetris Company, sums it up when he says: " Tetris is simple to learn, hard to master and its addictive nature makes it something special."

Rogers may be right, but his answer may not go far enough for those who don't know the ins and outs of Tetris, so let's go right to the source: its inventor, Alexey Pajitnov.