Apple's giving us a patent application peek into its post-PC future, and it looks like hard keys will be so 2008. The recently revelead filing shows off a virtual, flat keyboard concept for Cupertino's line of non-iOS products that flirts with metal, plastic and glass form factors. Using a combination of piezoelectrics, haptic feedback and acoustic pulse recognition, these prospective designs will be able to detect your finger-pounding surface input. If you're the fast-typing kind, you're probably wondering how your digits will recognize the keys sight unseen.