Nice! Reminds me of this very relaxing video:

http://vimeo.com/9498805

What's more interesting is how much energy there is in just that screen's surface area of sunlight. Enough to turn sand molten in under a second. Thinking of just how far away that is from the sun, and how much more surface area there is in a sphere with a radius that size..

This is really cool, although leaving that size of fresnel lens uncovered makes me nervous.