There are exercises at the end of each chapter. Most exercises ask you to implement something new in pbrt, often something described in a (SIGGRAPH) paper. Pbrt

There are exercises at the end of each chapter. Most exercises ask you to implement something new in pbrt, often something described in a (SIGGRAPH) paper. Pbrt is very modular and it's quite easy to add a new acceleration structure, a new shape, a new light, etc. I haven't done these exercises myself though, I mostly use the book as a reference while implementing my own renderer.