I've had this idea floating around in my head for a while now, and would love some input. If someone were to take up the task of making their own movement, disregarding patents and everything else that might get in the way, how difficult (the definition of difficult being genuinely hard to figure out, not time consuming, because time isn't an issue) could it actually be? Say you want to start from scratch and you have the math, metal, jewels and tools to do it. I'm talking about a movement, not a case. The only thing that might need to be borrowed would be a hairspring.

The possibility of recreating a movement is ok. I'm more interested in the development and construction process.