WarpTris is a rather different (and original) kind of Tetris, instead of pieces dropping from the top side of the Game window, they appear at the middle of it, and then start falling towards one side, randomly.

This behavior, has a pseudo-Physical explanation: imagine your in Space, where there's no gravity, if you drop something, and give it an impulse in a given direction, that's the direction it will start moving (or falling), and it will continue moving that way, unless it encounters something on its way. So on WarpTris, pieces appear at the middle of the Game window and then receive an impulse, in a random direction, and immediately start falling towards that direction (just like in space).

The piece can only fall towards four different directions (Up, Down, Left and Right), and you can make lines on the four sides of the Game window. You loose when some piece covers any square on the middle gray area. There are three levels of difficulty, which I call impulses (it makes more sense). What is different between them is the impulse strength, thus having direct implication on the speed at which the pieces move.

Finally, when you make a line on one side, only the area from that side of the game window, to the first parallel side of the middle gray square will be evaluated, which opens holes on the adjacent sides of the Game window. For example, the figure on the right shows which area will be evaluated, if you make a line on the left side of the Game window.
Note: You can only move your piece parallelly to the side it is falling to.