“In the universe of movies, music, books, and articles, the assumption is that you need permission to make use of just about everything (or that you have a reason not to need permission, such as fair use). After all, the difference between downloading a song legally and downloading it illegally largely comes down to whether the person who controls its rights gave you permission to do so. In the physical world, the assumption is just the opposite. In the majority of cases, you do not need anyone’s permission to copy, improve, or build upon an existing object. Broadly speaking, copyright does not apply to so-called ‘useful objects’—objects that do something besides look nice. Giant sculptures in the middle of Washington, D.C.? Protected by copyright. That broken hinge on your old record player? Not protected by copyright.”

– Wondering how copyright law applies to physical objects, especially ones you might want to replicate using a 3-D printer? Please allow my boy Michael Weinberg to break it down for you in Slate.