"Mathematicians describe tendril perversion," by M. N. Jensen. ScienceNews, 28 February 1998, page 134.
Telephone cords usually lie in a single neat coil which like a spring twistsonly in one direction. But sometimes the coils develop kinks, suddenlyreversing the direction of their twist. Such a change of twist direction, alsofound in the tendrils of climbing plants, is known as "tendril perversion."According to the article, mathematicians have discovered that these reversalsof direction "result from the curviness inherent in tendrils and cords."
--- Allyn Jackson