Physicists untangle the geometry of rope

Twine, string, cord or cable, it all winds up the same way

Researchers have unraveled the mathematics that keeps ropes from unwinding.

TWISTED SKEIN A triple-stranded rope, like the one shown here, reaches a “zero-twist configuration” when its individual strands are rotated to their maximum — resulting in a rope that’s 68 percent shorter than the length of its individual strands, no matter the material.