Feature Research

Passiflora edulis tendrils and cellulosic fibers form helices and spirals.

Note the helix reversals – “perversions” – indicat- ed by arrows in (A) and (C). Tendrils and fibers, if supported at both ends, twist into a helix of one handedness over half of its length and of the opposite handedness over the other half, the two halves being connected by a perversion. If supported at just one end, they curl into spirals (B) and (D).

SoftMatterWorld Newsletter 22, October 2010, SoftMatterWorld