I have a rope in my back yard for practice.
Currently, I have a chain around a tree limb attached to a triangular screw link and small screw link and small descending ring attached to that. I have been able to use a single rope pulled through that. The rope is held in place by a washer (from On Rope book) in front of a stopper knot. After that is a figure 8 with a carabiner that I put back on the rope the first time I ascend. I have a small rope on the carabiner I use to retrieve the rope. It works, except I think it would all be easier to run the rope through a pulley and have the system stop against the pulley. I confirmed that the washer or any of the knots would stop against the pulley, so the size is good, and it seems solid to me. I cannot find evidence of others using this application, though. Any opinions regarding if that would be a safe application to have a knot block against a pulley?