The hyperbolic surface, which has so-called negative curvature because its surface curves up and down at the same time, like a saddle. 双曲曲面,即通常所称的负曲率,因为它的表面同时向上和向下弯曲,就像一个马鞍。
Curvature of the surface prevents slump block from becoming completely detached. 表面的曲率防止滑塌块完全脱离。