[defertoreptar]

Copyright does not protect game mechanics and rules. In Tetris v. Xio, they successfully argued that the game infringed on trade dress.

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."

[bitwize]

Xio did, in fact, attempt to point out that the shapes of the tetrominos are functional elements and not subject to trade dress. The judge disagreed.

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.

[defertoreptar]

In the ruling, the judge states, "The style, design, shape, and movement of the pieces are expression; they are not part of the ideas, rules, or functions of the game nor are they essential or inseparable from the ideas, rules, or functions of the game."

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.

[bitwize]

Well if you're sitting on a pile of startup exit cash and can hire a Boies-tier attorney, go ahead and write that Tetris clone. You'll get your day in court to test those theories of yours, soon enough, and you can appeal it all the way to the Supremes if you wish.

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.

[defertoreptar]

If you are new to programming, I would actually recommend making a Tetris clone. It's a great learning experience. Obviously if you're worried about receiving a cease and desist, then don't put it on sale on the app store.

[derefr]

Does U.S. case law matter if you create and distribute your game in a country that is not the U.S.?

Funny thought: what would happen if a student of the Russian Academy of Sciences created a Tetris clone? ;)

[balodja]

Two fun facts here.

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.