I feel like back then we didn’t find any cases backing up TTC’s claims, but I haven’t kept up over the years.
The upshot of this is that it is illegal to develop a clone of Tetris. It doesn't matter whether you call it Tetris or not, or whether you use "ripped" or copied assets or not -- the very fact that you have copied Tetris means you are infringing. It may be illegal to develop a video game that uses tetrominoes at all since the tetromino pieces are protected trademarks of The Tetris Company.
They claimed that the pieces looked like ones in other games, which in my view is impossible not to infringe on since there have been hundreds of Tetris games with every type of piece design possible.
They claimed that they used tetrominos, and the playfield was twice as high as it was wide, and so on. What Xio failed to point out was that all of these are functional aspects of the game, which means it is not protected by trade dress. Even the original creator, Alexey Pajitnov, has said that he originally tried pentomonoes, but that was too difficult, so he used tetrominos instead. That's functional, not trade dress.
Do you have a source for Tetris's trademarking tetrominos? Perhaps you're referring to their "tetrimino" label, which their own term for what the non-branded world refers to as "tetrominos."
The judge also said that while copyright does not protect the abstract concept of a falling block game, he specifically cited the shapes of the blocks and the playfield size as copyrightable.
It's settled U.S. case law. If you develop a clone of Tetris, you are infringing on The Tetris Company's copyrights and trademarks and may be subject to civil and criminal penalties under U.S. law.
IF YOU DON'T WANT TO BE SUED, DON'T EVER WRITE A TETRIS CLONE. PERIOD.
Funny thought: what would happen if a student of the Russian Academy of Sciences created a Tetris clone? ;)
First one. Russian Academy of Sciences(RAS) doesn't hold students. That's an authority that manages the network of research institutes. Educational institutes are separated from that network in Russia.
Second one. Pazhitnov really worked in one of the RAS institutes when created tetris.
Clearly the judge disagreed that these elements weren't protectable, but do you agree? I'm say that I don't agree with the judge. Changing the the kind of polyominoes will make the game easier or harder (imagine how easy it would be with dominoes). Changing the playfield dimensions also changes the difficulty: a lower ceiling as well as a narrower well makes it much more difficult to survive.
As things stand, though, the law of the land as established in federal courts says those elements are copyrightable, and under copyright. So it doesn't matter a fig what you or I think of the judge's ruling -- the law is clear.
It'd be like trying to trademark a d20. Sure, one with symbols/numbers on it, as viewed from a certain angle, stylized a certain way, might be trademarkable as a mark (i.e. a logo.) But isocahedrons generally? They're mathematical objects.
Which means that, presumably, you could make a Tetris clone as a board game (which would work a bit like Connect Four, I guess) without any exposure.
So yes, while the tetrominos being a Tetris Company trademark precludes their unlicensed use in video games, they can be used in other contexts -- a tetromino pattern on pyjamas or wallpaper, for instance.
However, I would be wary about attempting to use them in a board game, as I seem to recall at least one licensed Tetris board game in the wild. Consult an attorney before proceeding. :)
Tetrominoes are not a Tetris Company trademark. They have, however, trademarked the word "tetrimino."