I had long believed that the cruel, torturous selection of what bricks are coming next in Tetris was random. Turns out, they're not! Which makes sense. Nothing that cruel can happen by accident.
"Tetris doesn't deliver the bricks in a completely random order; it shuffles ahead a set of bricks", Goldeneye designer Martin Hollis tells Gamasutra. "If I recall rightly, about four sets of seven. What that does is it evens out the distribution, so it means you won't get a load of S or Z bricks. You can't possibly get more than say, seven in a row."
"These kind of tricks don't make games worse, they put a lot of work into that and they believe that it makes the game better. I'm inclined to think that it does. But, it does isolate you from the brutality of true randomness."
Imagine getting more than seven "S" blocks in a row. Just imagine the feeling. You'd either kill yourself, or spend the rest of your life hunting down the man who invented Tetris, just so you could kill him.
Column: "Gambrian Explosion": Games, Randomness, and The Problem with Being Human [GameSetWatch]