Random...

Found this rope today and was inspired to demonstrate the prusik knot - it's essentially a locking knot used to slide one rope along another as in jumaring. It can also be used to make temporary loops like this one that can hold a good amount of strain without coming loose when tension is released. I believe this was somehow used for a quick and easy method of hogtying POWs back in the day, but now flexcuffs just work so much better.