Did you know that Apple once developed its own in-house Tetris clone, Stacker, during the development of the third-generation iPod? Stacker never saw a mainstream release, but three years following the 3rd Gen iPod’s May 2003 release date, an officially licensed iPod Tetris was released across most existing iPods in 2006, developed by Electronic Arts. And of course, these days pretty much any smart device can play Tetris without issue — but back in ’03, the most mainstream pocket Tetris handheld was more likely to be a Game Boy (Advance) than a media player or a phone.

The existence of this iPod Tetris clone, Stacker, was brought to our attention by YouTuber Apple Demo, revealing gameplay of the long-lost software on a prototype 3rd Gen iPod.

So, let’s talk a little more about this prototype iPod and how Stacker plays on it. In order to get the prototype functioning, Apple Demo had to acquire an existing iPod 3rd Gen ribbon cable and get the device to boot from its original drive. Analysis of the device’s labeling reveals it to have been a Design, Validation, and Testing (DVT) model made on week 14 of 2003, just a few months before the full release.

According to ex-Apple engineer Tony Fadell speaking to Apple Demo, Stacker and the other games available on the prototype iPod unit were never released “Because we added games with later software releases” — which would particularly apply to Stacker, since an official Tetris port gives a much more premium feel than an obvious knock-off.

The final gameplay of Stacker requires rotating the touchpad clockwise or counter-clockwise to push the pieces right or left, respectively. The center button lets you flip pieces on tap, and it seems to also function as the accelerated fall button when held. Overall, the game is a fairly functional if barebones Tetris clone, and Apple Demo plays it for a few minutes in his video coverage, to show off how it actually looks in motion.

Three other games on the prototype unit not demoed in the original video include Block0, Chopper, and Klondike. At the time of writing, we have no details on these, but Apple Demo will likely cover them eventually.