Another one.

A sludgy wallpaper, made in Gimp by setting the sparks brush to 'take colour from gradient', and using different gradients, overlapping at places. Then selecting the white parts and doing a round of it on them.

I have made one more. But I'm not giving it up right now. Because I love it lots. ;) Not really; I'm gonna put them up one at a time from now onwards. Or else they get exhausted too quick.