Original author: Eugeniy Mikhailov
Conversion from Octave to Python: Bain Bronner

Language: Python 2.7xx
Requires: numpy 1.6.x and scipy 0.10.x

prismDiskCoupling.py calculates and draws the critical angle for a given prism geometry and indexes of refraction for the prism and disk
demoPrismDiskCoupling.py is an example call of the above function

beamTrace.py traces the beam according to Fresnel equations with lighter colors indicating less intensity
exampleBeamTrace.py is an example call of the above function

the rest of the functions serve as helpers to the above

changes:
	1) in converting to Python, the beams initial travel angle and start position for the exampleBeamTrace were determined by a slightly modified prismDiskCoupling.py
	2) slightly different annotation styles, including the use of arrows, for the angles in prismDiskCoupling
	3) variable and files converted to python naming standard, i.e. this_is_a_file.m --> thisIsAFile.py
	4) more or less same logic and mathematics as previously
	5) disk placement was added, so now the disk is not always assumed to be in the center