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.

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.

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.

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? ;)

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.