Ray tracer based the book "Ray Tracing in One Weekend"
To compile on OS X El Capitan (10.11.6)
g++ -o rt rt.cpp -L/usr/include/c++/4.2.1/
To run
./rt > img.ppm
To view output you will need something to view images in PPM format. The book recommends ToyViewer. You can also get this from the AppStore.