Intro lesson

Here is a sketch of the first three lessons according to the lesson plan.  There is a snag though:

For these lessons I want to start off slow by having the students write just snippets of glsl code instead of jumping right into full shaders.  However, this seems difficult to do with glslify-live.  Do you have any good ideas on how to make this work?

I figure we could merge this as is and I will move on to writing the other lessons separately.