Akaka Falls, Hilo side, Big Island Hawaii. "Optical" (brain) illusion. DSC_0905
Here's a big, tall, waterfall in 5600 X 3500 pixels - zoom in or download the original to see it all. There's a wonderful optical illusion as you stand here on the overlook, watching. The water falls, and falls, and after a minute of letting your eyes rest on it falling, falling, look left or right and you'll see a stripe of the greenery appearing to *rise* at the same rate! The "eye", meaning the eye and the brain, recognizes the constant motion and tries to subtract it. Just in that stripe. Because we are a visual species. and a more easily understood image was an advantage to some long-lost ancestor.