Difficult to understand; complicated.
Turned inward at the margin, like the exterior lip of the shells of species in genus Cypraea.
Having a complex pattern of coils in which younger whorls only partly surround older ones.
Rolled inward spirally.
Having the edges rolled with the adaxial side outward.
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.
To roll or curl inwards.
Impossible to resolve; insoluble.
Impossible to separate into its component parts.