Hmm, could this be a close up of elephant skin?
Or is it tree bark striations, perhaps?
Maybe a close up of lizard skin? Or intestines?
Swirling, boiling lava?
Decomposing algae and spatterdock leaves?
Yes, I'm afraid so. Some still, enclosed coves don't get flushed out much, and are in this state at the end of the season in Lake Arrowhead. It's what is covering the water surface in the foreground of this pic.