This case is about a trademark, not a patent. Any word or symbol that identifies a source of goods can be a trademark. Hence Apple getting a trademark on using the word "Apple" to sell computers even though people have been using the word "apple" to refer to fruit for hundreds of years. (The same goes for "Amazon" despite the river, "Windows" despite the ventilation system, and "Beats" despite the existence of rhythm). If one tried to sell computer parts under the name "Apple" or any reasonable variant thereof, it wouldn't be a defense to say "look, there's a fruit called the same thing."

The real problem here is that Zazzle caved in based on a weak letter about the trademark -- not that the trademark office somehow failed. If Apple Inc sent a letter to Zazzle asking to remove all references to the word "apple" in Zazzle, the problem wouldn't be that Apple's trademark is invalid (it's perfectly valid for selling computers), but rather that Apple would have stretched its trademark too far (it only grants the right to control uses related to selling computers). Same here. Somebody could quite reasonably sell computer products under the name "Pi" (see Raspberry Pi for example), but that wouldn't grant the right to remove all references to the number from Zazzle.

Generally I think it's a sort of two-step the patent/trademark trolls do. They go to USPTO and apply for IP based around a narrow reading of their application, and then they attempt to enforce based on a broad reading of their IP once they have it.

The narrow case here (that a trademark can be "pi" plus some additional character) is not super far-fetched (though maybe the period isn't enough). But then the broad case (that anything using "pi" infringes) is the excessive bit. It may have appeared totally clear to the guy granting the trademark that "pi dot" wouldn't grant any claims to "pi", but its not clear to enforcement authorities.

This is compounded by this sort of stuff almost never seeing the inside of a courtroom. Patent trolls push for settlement so they never have to litigate their broad claims on their patent, and they can move against trademarks with a cease-and-desist or DMCA claim, which basically every company folds to without reading, on the advice of their lawyers.

A is for Apple™...

Yes, this definitely seems like a mistake on Zazzle's part.

And it's possible the artist may have been acting in good faith, and only wanted designs that actually copy his brand removed, not all designs featuring pi.

Edit: OK, it does seems like the artist is also abusing the system here, judging by his other trademark: http://news.artnet.com/art-world/artist-who-trademarked-pi-s...

ESPECIALLY when the C&D talked about copyright infringement.

Yes and yes. "IBM" doesn't form a word, but it's a perfectly valid trademark and you would be sued into oblivion (quite fairly at that) for trying to sell computer software or hardware as "IBM." Gatorade has a trademark on a capital "G" in the field of sports drinks because consumers have come to recognize the "G" line of products. "Google" is a mostly-made-up word (it was at least unfamiliar before Google became popular) and it is a valid trademark. "Apple" is a commonly known word and it is also a valid trademark. The symbol for Prince [1] is an arbitrary symbol that could also be trademarked.

The key fact is that trademarks protect the right to use a word or symbol in connection with selling goods or services in a certain field. Apple doesn't get to ban all uses of the word "apple" but you couldn't go sell your own products as "Apple Computing Stuff". Prince can't ban people drawing the symbol linked above, but he could sue anybody who released a CD with that as their cover artwork. Gatorade doesn't control all uses of the letter "G" but I wouldn't try selling a sports drink with just a capital G on the bottle.

Zazzle done messed up, but not because letters or symbols alone couldn't be trademark.

[1] http://en.wikipedia.org/wiki/File:Prince_logo.svg

Looks like your regular old Times New Roman font.

http://graphemica.com/%CF%80/glyphs/times-new-roman-regular

http://www.scribd.com/doc/227367808/Zazzle-Pi-Trademark-Lett...

The trademark covers exactly the "π" symbol displayed in the [Wiktionary page on Pi](http://en.wiktionary.org/wiki/pi#English) followed by a period ".".

The guy did not create his own font. Zazzle just started pulling all the things with the π symbol on them, because as I'm sure everyone is aware, nobody has ever thought to put π on a T-shirt before, so obviously this guy's trademark on "π." takes precedence over all the copycats!

Money, please.