Apple likes to program randomly useful tools into their iPhones, like the hidden magnifying glass and the backspace shortcut on the calculator app. As Simplemost reports, the Apple logo on the back of your iPhone is actually a button that can execute various tasks. From there, you can choose Touch and then Back Tap to program the Apple logo to do all sorts of things at the tap of your finger. You can even program the phone to perform different tasks depending on if you double tap or triple tap the button. The software update uses the pre-existing sensors in your iPhone to transform the back of the device into a brand-new button.