This is a simple variant of a locking bracelet I designed for the Engineer's Day Open House, February 28, 2015, at the University of Kentucky. The version handed-out from my lab had the UK logo on it, this one has the words "3D PRINT STRONG" on it... and strong it is! Despite printing in PLA just 2 layers thick, the tiny interlocked-3/4-circles can hold scary weights without unclasping: note the photo with the fish scale confirming it doesn't even come close to unclasping at 21 pounds of load.