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   Ray Marching demo by Kevin Roast
   
   - Lots of code/ideas for this demo come from reading:
     http://www.iquilezles.org/www/material/nvscene2008/rwwtt.pdf
     http://www.pouet.net/topic.php?which=7931&page=1
     http://www.pouet.net/topic.php?which=7920&page=1
     http://iquilezles.org/www/articles/distfunctions/distfunctions.htm
     https://www.shadertoy.com/
   
   If you want to understand this stuff read through the PDF and pouet.net links a