Apex angle is A = 60 degrees.
Expected index of refraction is 1.5

Angle  X1     Y1     X2    Y2
-----  ---    ---    ---   ---
30     1.5    6.0    5.0   2.8
35     2.0    7.0    6.0   3.8
40     2.0    8.0    6.0   4.9
45     1.0    9.1    9.0   3.2
50     4.0    6.8   11.0   1.6
55     5.0    6.0   13.0   0.0
60     5.0    5.0    9.0   2.0
65     5.0    4.0    9.8   0.0
70     0.0    7.0    7.9   0.0
75     0.0    5.6    5.0   1.7