[zero__one]

From https://meatfighter.com/tetromino-computer/input-language.ht...

> In practice, IL programs direct the agent to construct a pile near the origin that progressively grows taller and wider. That being the case, it can work with a Tetris implementation that defines “row infinity” as a finite row whose index increases as a function of the number of spawns. In such an implementation, the agent emulates a semihard drop with a finite number of soft drops.

[woodrowbarlow]

that's not really infinite, though, and other pages do describe it as truly infinite, e.g.:

> When a newly spawned piece falls, it never gets closer to the floor due to the nature of infinity.

i'm nitpicking, of course. everything described is possible with a sufficiently large board. you'll just have a time constraint to place each block.

[zero__one]

For the method described in the paper to work, the infinite version of the game requires a semihard drop operation or something analogous as a legal move. In modern versions of Tetris, the rotation systems permit very unusual operations such as wall climbing or infinite lock delays, not to mention rotating in physically impossible ways. A semihard drop is not a big ask on an infinite playfield. It's within the spirit of the game.