Figure 5: How to fold a ring in an odd number of loops.
From: Overcurvature describes the buckling and folding of rings from curved origami to foldable tents
(a) Successive conformations of the ring for three final loops, corresponding to the path of least resistance. The numbers are the overcurvatures. The bottom picture is an experimental realization, where the starting ring was made by bending a steel wire of circular cross-section (1 mm diameter) in a hoop of 1 m diameter. (b) Successive conformations of the ring for five final loops.
