For people trying to explain why the image is transparent outside of the spiral, if you look you can see that it's transparent everywhere. I seriously doubt that the transparency has any meaning; more likely they just set the opacity in the CSS to make it look cooler. I mean, three quarters of everything on that mainframe was styled to be transparent glass so you could ogle the numbers floating behind it.
At any rate, the particles look like they were done with a scattered brush in Photoshop and then overlayed with some colors, explaining why colors spill out over the spiral and into the transparent areas beyond, meaning the original spiral layer was white. With its current setup, it looks pretty possible to see straight through to the original spiral (or at least the original spiral for this iteration of the image). I could probably trace over it and post here.
Founder of GoodSemester and ultra-webmaster of Zelda Universe and Zelda Wiki. I also have a blog that sometimes has ice cream.