saddle-shaped

[MonicaLes]

shaped in the form of a horses saddle

[Monty]

Saddle-shaped refers to a three-dimensional shape or surface that curves up in one direction and down in another direction, resembling the shape of a horses saddle. It is often referred to in mathematics or geometry when describing a saddle point or saddle curve, where the shape is concave in one direction and convex in the other.

[Kit]

bent down at the sides so as to give the upper part a rounded form