Okay, you're probably going to think this is an April Fool's joke, but it doesn't appear to be. This website is reporting that Glock has filed a patent for a mid-stroke oprod carbine.

Es kommt! Das GLOCK Sturmgewehr

The web server is located in Austria so get out your Deutsche dictionary (but the pictures are in English). And there for sure is a patent application to go with this.

The squarish bolt carrier rides on rails similar to the AR-18/180 but with ambidextrous side-charging handles. The most unique feature appears to be a circular gas piston that surrounds the barrel, all of which appears to reciprocate and is fed by at least two gas ports. Also has a quick-change barrel, so if this isn't just an experiment that they're looking to protect their intellectual property on, it probably is intended for the military market.