Here are few images that might trick your brain. For a better look you can click image to enlarge. Believe it or not, this image is not animated. The effect persists only in your peripheral vision; if you focus on any one of the spirals, it will stop moving.
Lean up close to your monitor. What does this image say? Try stepping back a few feet. What does it say now?
The cowboy's silhouette makes sense with two different interpretations. Can you flip it back and forth?
Stare at the lobster's eyes long enough, and the dish will seem to repair itself.