Contribute correction: The Ray Tracing Demo

  ______     ___                ______  
 /_   _//   / _ \\      ___    /_   _// 
 `-| |,-   / //\ \\    /   ||   -| ||-  
   | ||   |  ___  ||  | [] ||   _| ||_  
   |_||   |_||  |_||   \__ ||  /_____// 
   `-`'   `-`   `-`     -|_||  `-----`  
                         `-`