Dihedral Angle, Intersecting Planes, Model

####Dihedral Angle, Intersecting Planes, Model

A 3D model for explaining the Dihedral angle and other related ideas when two planes intersect in space. This was designed when I was trying to help a kid to design a Platonic solid. Of course, the Dihedral angle is closely related to the angle of the two intersecting normal lines. If G is a Dihedral angle, then PI - G is also a dihedral angle, depending on the perspective.

Using a 3D model, it is much easier to explain the ideas: normal lines, tamper or extrusion angle, and other connections.

#### Reference
1. http://mathworld.wolfram.com/DihedralAngle.html