### Scott M

* You say “pipes” and also “threads”.  This is a small thing but I wonder if you can reconcile those metaphors.  I think in terms of threads, but “pipes” makes more sense with your illustration.  Also works better with the concept of a “pipeline” or “graphics/rendering pipeline”.

### Nicolas B

* clearly answer the "what is a fragment shader?" question in some sort of recap paragraph.
* beef up explanations around the compilation step (a brief overview will do).