I found this supplementary write-up from UT Austin very helpful in better understanding Gauss' ray tracing: https://web2.ph.utexas.edu/~vadim/Classes/2014f/rays.pdf
I found this supplementary write-up from UT Austin very helpful in better understanding Gauss' ray tracing: https://web2.ph.utexas.edu/~vadim/Classes/2014f/rays.pdf