
The patent includes drawings of an iPhone 6-style smartphone, which features the standard home button configuration. But when a user puts enough force on the home button (more than just a standard click) it can extend to just a bit beyond the surface of the display, giving it leeway to move left, right, up and down and accept input on the x- and y- axis, as well as the z-axis (a downward press from above, the only directional input supported by the current home button design). Switching back is as simple as pressing down on the home button hard enough to lock it back into place.
Other patent details include the possibility of adding additional sensors to the home button mechanism, including a force sensor, an accelerometer, a gyroscope, a contact sensor, and optical sensor, a capacitive sensor, an ultrasonic sensor and more. That could make it a very comprehensive input device, which can detect more than a standard analog stick you might find on, say, a PlayStation controller.