Appropriately dubbed "Stack," the project was conceived back in the early days of iPhone hacks through a basic implementation of Mac OS X Leopard's 'Stacks' feature that allows iPhone users to keep a quick-launch list of their applications in their handset's dock. It was written by Irish developer Steven Troughton-Smith.
"The first iPhone OS device released in Ireland was the original iPod touch, which, then, sported a pretty semi-transparent Dock with reflections. I had known that I wanted to develop for the iPhone OS as soon as it was announced, but it was only on reception of my first device that I saw what I wanted to create," he told AppleInsider. "The iPod's Dock was so alike the Leopard Dock that I just had to try to create an implementation of Leopard's 'Stacks' feature for the iPhone. After some work, and learning about CoreAnimation (then LayerKit) on the fly, the app was ready to run. It was a far cry from perfect, but it worked."
This was October 2007, and several months later when the iPhone SDK was announced it became clear that 'Stack', as the application was called, would not be acceptable for distribution on the App Store due to its nature.
It's been roughly two years since then, and the developer has taken another stab at making his solution more tidy and fluid, and as close to an official Apple implementation as possible. The Stack v3 (demonstrated below) is a ground-up rewrite that turns the plugin into an actual icon on an iPhone's home screen. Users can drag and reorder it anywhere, as they wish, and can also apply a single gesture tap to fan the stack out into a menu of applications that are ready to be launched. To add icons to the Stack, users simply drag and drop them right from the home screen. Stack v3 is now more than just a concept, but only runs on jail-broken iPhones.
"Unfortunately, I can never release this officially, but it showcases one of the awesome possibilities one could have on their iPhone if Apple were to enable a safe and sanctioned way of writing plugins to other applications, or to SpringBoard (the home screen) in particular," Troughton-Smith says. "I can't stand having a Jailbroken device, but it's the only way I have of running Stack. I know many people would enjoy an official 'Stack' feature on iPhone OS, as the several hundred thousand downloaders of the previous version prove."
As can be seen in the video above, Stack v3 makes it possible to launch an additional 15 applications from the handset's primary home screen, or any other page of apps given that it integrates with the stationary dock. Additionally the concept aids in the currently tedious process of reorganizing multiple screens of iPhone apps.
A version of the app run in the iPhone's simulator provides some additional clarity on how Stack v3 functions: