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 revealed 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. Well, there's a few workarounds for that. In its metal and plastic iterations, Jobs and co. plan to stamp or micro-perforate the layout into place, while their glass counterpart would receive a graphical overlay. The application also promises an LED-lit display for hard to see conditions and the inclusion of capactive sensors to enable multi-touch functions, so you avoid e.e. cummings-style emails. Of course, applications aren't necessarily indicative of a surefire product, but those interested in tickling their imagination can give the source link a look.