Erm, with that, I kept duplicating layers and rotating them 90 degrees, setting the layer properties as \"lighten\" (In the blending options). To make the first layer, I just used gradients and difference clouds. That one took a while though, I ended up with like 20 layers...

Edit:
And what about the copywrights at the bottom right... do those actualy mean anything?
They are so nobody thinks I stole the images from someone else, and so nobody steals them from me. Of course, anyone with the most basic knowledge in graphic art could crop it...But, eh... It keeps the noobs from stealing \'em.