This is an example of a bistable mechanism. A bistable mechanism has two natural states. It wants to settle into one of two positions at any given time. This is a special method of designing multi-part assemblies pre-assembled and is exclusive to 3d printing. The parts are design in a way that makes it impossible to take apart the assembly without breaking a component. Printing suggestions: No supports needed. I highly recommend using a flexible build plate for easy part removal.