You want to climb to the top of a very tall hanging rope (never mind what's up there). You expect to get tired along the way, too tired to continually grip with your hands. How do you do it?
Gadgets, harnesses, etc. are permissible. I don't have any magically clever solution in mind, only some crude, untested thoughts that for the safety of impressionable youth I'll keep to myself. Also, I asked a friend who says this is a solved problem in rock-climbing circles.
What interested me as I thought about this is how the requirements and mental verification process resembled algorithms work. The climber wants to loop thru a basic routine to create progress ("climb-a-bit"), with a safety invariant ("securely fastened") assumed at the beginning of the routine and reestablished at the end. Efficiency-type considerations also come in play--the amount of rope around the climber's body and the complexity of its arrangement and manipulations should stay bounded.
I've never done engineering, and maybe these analogies are pervasive enough that my observation would seem vacuous to someone in-the-know. Still, it's nice to dabble in problems that have conceptual affinities with math I study without necessarily being reducible to math.