This example demonstrates how to display obstacle loss that happens during radio
signal propagation. Obstacle loss is twofold: dielectric loss is caused by the
object's material, reflection loss is caused by entering and leaving the object.  

The ad-hoc wireless network contains 2 nodes. The source node continuously pings
the destination node through a simple physical wall. Both nodes move up and down
but they always stay at the opposite sides of the wall.

When you run the example, the obstacle loss visualizer displays the intersections
between the radio signal propagation path and the physical object. It also shows
the face normal vectors for the intersections where the signal enters or leaves
the object.
