I have a plastic slinky that I fiddle with — I twist it and twist it, and then release it in a controlled spin. Sometimes I lose control of the unwinding and the slinky contorts into a tangled mass. Then I disentangle the mass. This is often pretty easy, but I just recovered from a pretty hard one..
..the interesting thing about it was that at some point I could see my hands doing something to the slinky, and I knew it was working, but I wasn't sure what my hands were doing exactly. They were twisting and pulling in some controlled say, using some resistance of the slinky to guide them.. now I know my subconscious seems to build models of systems and figure out ways to manipulate and solve them, but usually this happens all inside my head, and it was interesting to witness it happen outside my head..
..of course, even walking falls into this category, or juggling, but those things are more about learning to use my own muscles, more-or-less. Solving the tangled slinky was learning to correctly manipulate the parts of an external system..
..I suppose this happens when untying knots too, which I've tried, but there it seems like just random manipulations to "losen things up" is all that's happening.. here, it was clear that my hands were doing something seemingly random, but definitely not. I could see it working, and the process did in fact lead to an untangled slinky.