The Tetris Company sent one of their infamous bullshit threat letters to Apple and the author of this (very good) free Tetris clone.
Their claim, as usual, is completely unenforceable and would never hold up in court. They know this. But they also know that indie developers are unlikely to have the cash to spare on lawyers and court proceedings, so they send bullshit letters like this all the time that threaten legal action until authors bend over for them. Like our friends at the RIAA.
It’s important to note that The Tetris Company’s claims aren’t just against the “Tetris” name (for which they can more legitimately claim) — they won’t let you make a game that resembles Tetris regardless of what you call it, even if you use 100% original names, artwork, and music. IANAL, but that sounds more like a patent claim (which they don’t have), not something that copyright can cover.