Interestingly enough, after a bunch of leaked patents regarding a radial menu for Android, now Apple comes up with a similar system. On March 20 2014, the US Patent & Trademark Office published a patent application from Apple, that reveals details about a radial styled menu system.
That system is meant for both the iOS and Macs. The first radial menu patent from Apple became popular in November 2010 and now a more advanced system is back. The new documents show some sorts of radial menus that work with a digital pen, pretty much like Samsung’s Air Command with the S Pen. As you can see in the images published here, the icons are gravitating around a center core and they can be navigated within by touches.
The radial gestures will open sub menus and the subsequent display of the sub menu. For some reason, I would imagine a circular collection of icons on an iPod Touch, not exactly on an iMac… This could be included in a certain area of the screen, maybe like a taskbar or toolbar or something.