This is more of a stamp, but if you drag it along as a brush you can create some pretty neat running trails. The other one is just grass.
http://www.thelinkup.com/shared/hxc4xwu1smu1
I'm a Newbie but I'm pretty sure this qualifies as Abstract. Salvadore Dali had melting clocks, I have Magnified Smileys
http://www.thelinkup.com/shared/lrb3ygs3vuw4