The magic world of geometry. III: The Dirac string problem (Q1897197)

[For Part I see Zbl 0812.52004, for Part II see Zbl 0809.57005).] Consider a solid body connected by an elastic string to a post and by another two elastic strings to another post. Dirac's problem of removing the twist obtained by a double rotation about \(2 \pi\) for the two strings through continuous deformations is solved by using arguments from the theory of braids.