Toy construction sets like Legos and Krinkles can provide an incredible creative outlet for individuals of all ages, but with their own connector types and configurations, most of the systems are designed to work best within their own ecosystems. Coming to the rescue is the Free Universal Construction Kit, a set of 80 blocks designed to let 10 different building systems play nice with one another, from Legos to Duplos, to Gears! Gears! Gears! and Krinkles. Even cooler, the kit — put together by F.A.T. Lab and Sy-Lab — isn't a physical product unto itself; it's a set of 3D models suitable for use with Makerbot and other 3D printer systems. The files are available for download on Thingiverse now, and the entire project seems to be a wonderful way to encourage creativity and get some additional life out of those building blocks your children may have had when they were younger. Just don't let them figure out the Free Universal Construction Kit's rather adult-themed acronym.