Surfaces can be flat or curved. They can face to or away from a vantage point. Virtually all objects whose shapes can be perceived are combinations of surfaces. Surfaces form corners - concave or convex. Convex corners can form occluding edges.
Rounded surfaces can offer occlusion too.
A convex corner arises with some rounded surfaces, like teeth. If pictures can show edges of surfaces, they can show much of the visible environment. Klatzky et al - blind can do route tasks including short cuts. Klatzky et al - stress fixed procedures in tactile exploration. Property Procedure texture rub hardness press temperature static contact weight lift and unsupported holding volume or size manually enclose precise shape follow edge with finger 25.