Rope is useful for improvised weapons (the rope extends one's reach, making a longer lever arm; see meteor hammer, sling) and for traversing walls. Well, okay, and then there's that.

e — a cable, made of three hawsers
g — a hawser, made of three strands
h — a strand, made of three yarns
a — a yarn, made of individual fibers

NOTE that each layer is twisted in the opposite direction from the layer below

starting materials

• toilet paper [MythBusters]
• hair
• plastic bags
• plant material
  • cotton and wool are extremely common materials for yarn nowadays
  • stinging nettles have been very commonly and widely used in antiquity
    • the goal is to extract the bast fiber
  • dogbane
  • bark
  • dogwood
  • industrial processes used to extract bast fiber (especially from hemp, jute, or flax)
    [1] [2] [3] [4]
  • more
• fabric — in a prison setting, clothing / bedding can be torn into strips, and used to create yarns

preparing wool/cotton for yarn-making

creating yarns

• drop-spinning [1]
• plying yarn with a drop-spinner [1]

rope-making — by hand

rope-walk machines — simplified (3 pins + 2 boards)

rope-walk machines — with gears or belts