As far as I know, the general consensus is that you can't, but I've seen this case mentioned in several places as implying that maybe you can. I (not a lawyer,

As far as I know, the general consensus is that you can't, but I've seen this case mentioned in several places as implying that maybe you can. I (not a lawyer, just to be clear) find this case a bit confusing because there are several places where the court seems to conflate mechanics with their presentation/rendering. After reading about it again/more, I think it might be that people are reading a specific line of reasoning about merger doctrine as applying to copyrightability in general, when it's actually only addressing one part of the overall question of copyrightability and is still accepting that mechanics can't be copyrighted per se because they're functional. But this is still an impression and not something I can rigorously argue at this point, so be sure to consult your lawyer before writing a Tetris clone, I guess.