I am particularly interested in those structures with angles and lines. Sometimes it even doesn't have to be a firm one. It's also very interesting to see that when the little planes don't match the lines and there're always overlapped parts where appear new patterns and colors.

When using different materials as the surface, various effect are shown like the shadow combined with the lights, or the reflection under the sunlight from the glass wall. Sometimes it can make up different views (/shapes) if you stand at the same spot and watch it at different times (with the lights changing).