Title text:
The draw-by-repetition rule does a good job of keeping players from sliding a tile back and forth repeatedly, but the tiles definitely introduce some weird en passant and castling edge cases.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3139/
In some aspects this results in situations that the original Star Trek 3-D chess has with its movable platforms. The issue with chess variants is always how it adds while not unbalancing the game, and that's a difficult thing to test since chess by itself is complex even with its simple rules.