The term "tendril perversion" was coined in 1998 by mathematicians Goriely and Tabor to describe the long-observed phenomenon of coiled cables, vines and other helixes that have one kinked loop that goes the other way.
It's a gorgeous term, with its origins in 19th century topological literature, when "perversion" had a wider range of meanings.
The term "tendril perversion" was coined by Goriely and Tabor in 1998 based on the word perversion found in the 19th Century science literature . "Perversion" is a transition from one chirality to another and was known to James Clerk Maxwell, who attributed it to the topologist J. B. Listing.[3][5]
Tendril perversion can be viewed as an example of spontaneous symmetry breaking in which the strained structure of the tendril adopts a configuration of minimum energy while preserving zero overall twist.[1]Tendril perversion has been studied both experimentally and theoretically. Gerbode et al. have made experimental studies of the coiling of cucumber tendrils.[6][7]
A detailed study of a simple model of the physics of tendril perversion was made by MacMillen and Goriely in the early 2000s.[1] Liu et al. showed in 2014 that "the transition from a helical to a hemihelical shape, as well as the number of perversions, depends on the height to width ratio of the strip's cross-section."[2]
Tendril perversion [Wikipedia]
(Image: Cucurbita pepo 02 ies, Frank Vincentz, CC-BY-SA)
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