It is unclear how far Apple intended to take the clone and present it to fanboys who would think Steve Jobs coded it. The game has only been found on a prototype version of the third-generation iPod, indicating the company was experimenting with releasing the game on the music player in 2003.

It’s called Stacker and is controlled via the iPod’s scroll wheel. The software was spotted by X user AppleDemoYT, known for finding rare prototype devices.

The prototype iPod is a "DVT" device, meaning it was a mid-stage device still in "Design Validation Testing." Its model number is A1023, which is not a known model number for any iPod version.

The device runs a prototype version of iPodOS 2.0. The pieces are moved from left to right using the scroll wheel and fall when the middle button is pressed. The goal is to clear lines and score points so not so much like Tetris as completely identical.

Apple might have been shy of taking the idea after court battles erupted over the game after its inventor, Alexey Pajitnov, obtained full rights to his game in 2002.

It appears that Apple decided to play it safe and later versions of the iPod got an official version of Tetris, in addition to games like Bejeweled, Mini Golf, Mahjong, Zuma, Cubis 2, and Pac-Man. All of these releases predate the App Store.

 Apparently, one of the company’s main jobs is regularly calling Apple and asking it to remove illegal versions from its app store.