Braided Bookmark (no AMS!)

This little bookmark is surprisingly sturdy for not being connected at the ends. I was initially worried that it would fall apart too easily to be useful, but I quickly found that wasn't the case at all. Once braided, the three individual waves hold together remarkably well and will likely never need re-braiding unless intentionally disassembled.

It was more difficult to put together than I'd anticipated. In fact, putting it together was a long and difficult process that culminated in my younger brother completely showing me up by dexterously weaving it together with what seemed to be minimal thought and effort. My twenty minutes of unsuccessful fiddling with it didn't go entirely to waste, however, because I feel that I'm now more or less equipped to describe the process to someone else. So here we go.

ASSEMBLY INSTRUCTIONS (Note: If you want to puzzle out the assembly yourself, stop reading here)
The three STLs all have unique shapes and must follow a specific path within the