involute

Difficult to understand; complicated.

These vulgar, pleasure-seeking people, so frank and clamorous, were too uninhibited for his shielded and involuted life.

Having the edges rolled with the adaxial side outward.

Furthermore, the free anterior margin of the lobule is arched toward the lobe and is often involute[…]

Having a complex pattern of coils in which younger whorls only partly surround older ones.

Turned inward at the margin, like the exterior lip of the shells of species in genus Cypraea.

Rolled inward spirally.

To roll or curl inwards.

A curve that cuts all tangents of another curve at right angles; traced by a point on a string that unwinds from a curved object.