The code we have been writing on the stream.
I've added a few comments so it's not exactly the same, but close enough.
(ql:quickload :play-with-verts)(in-package :play-with-verts)(play :start)
If you are new to lisp I recommend waiting a few weeks until the next quicklisp release, then all the code you are seeing will be available through quicklisp and should just work.
The license covers everything except the pngs, which are from http://seamless-pixels.blogspot.no/2012/09/free-seamless-ground-textures.html