I could say I started my career in graphics writing shaders, with Rebelthink.
However it has been a long time since I played with actual shaders. Production shaders at Pixar can be complex, and interesting, but most of my time has been focused on supporting the pipeline that lets our artists do what they do.
So, there has been a pet project I have been delaying for months now. My good friends Inigo and Pol put together a website that lets you write any custom single pass fragment shader, and make it do whatever you want. There are many of great examples right on https://www.shadertoy.com
While the initial learning curve can seem daunting, the reward is almost immediate, and it's almost magic. There is a ton you can do with a single crazy fragment shader.
Disclaimer: you wouldn't want to put any of those shaders on a real game, they tend to be slow and there are so many better ways to do impressive effects. That's why it's called Shader Toy. It is great though, for testing new ideas.
Anyways, here I was, writing a shader.
Why not write a simple ray marcher in it? Why not make my ray marcher calculate the distance from procedural primitives, such as spheres?
Well, I kept fancifying my spheres, until they started looking like Manta Rays.
Why manta rays, you ask?
Because they are beautiful creatures, and because I remember how jealous I felt when my friend Philip posted a picture of a Manta Ray, from his very first trip diving in Hawaii.
If you know any shading or glsl, or even any programming at all, give it a try! It will be worth your while.