Problem
1. Write a program that uses the depth-sorting method to display the visible surfaces of any given object with plane faces.
3. Develop a depth-sorting program to display the visible surfaces in a scene containing several polyhedrons.
3. Write a program to display the visible surfaces of a convex polyhedron using the BSP-tree method.
4. Give examples of situations where the two methods discussed for test 3 in the area-subdivision algorithm will fail to identify correctly a surrounding surface that obscures all other surfaces.