Posted on Twitter by Nimblebit's Ian Marsh, the letter contains side-by-side screenshots of Tiny Tower and Dream Heights which suggest Zynga has lifted not just the concept, but much of its execution as well. Players build skyscrapers, fit out individual floors as shops to be restocked and apartments for workers to live in, and drop off visitors at the floor of their choice. Tiny Tower's twin currency mechanic also appears to have been lifted.
"Dear Zynga (all 2,789 of you!), we noticed you are about to launch a new iPhone game called Dream Heights," it reads. "Congratulations! We wanted to thank all you guys for being such big fans of our iPhone game of the year Tiny Tower!
"Good luck with your game, we are looking forward to inspiring you with our future games! Sincerely (all three of us), Nimblebit."
In a later tweet, Marsh claims the app binary calls the project Towerville, and the inhabitants Zitizens – Tiny Tower's are called Bitizens.
While Zynga's done similar in the past, taking such obvious inspiration from a well-known, successful indie game – one that was named best US iPhone game of 2011 by Apple – is arguably a new low for the company. In December, Zynga settled a lawsuit against Brazilian social game developer Vostu, which it had accused of "blatant copyright infringement."
When the suit was launched in June, Zynga's general counsel Reggie Davis said: "Blatant infringement of our creative works is not an acceptable business strategy – it is a violation of the law."