Your eyes adapt, though. Compare the shadow patches on the right side versus the shadow patches on the left. The left side is much clearer in the light patches, but the right is more consistent overall (supporting what cauterized says above about shadows).<p>Another sleeper issue with rapidly changing light and dark patches is that if you manage to get them to flicker around 10-14Hz (driving through light+dark patches), you&#x27;re going to provoke the occasional photoresponsive epileptic seizure. This has been seen in some roads in France where the trees were spaced in such a way that when the sun is low in the sky, it creates such a flicker. I don&#x27;t know what the rate would be for driving along that road at a normal rate, but I&#x27;d be curious to find out. If it&#x27;s a relatively short road, it would be unlikely to flicker long enough to provoke a seizure, even in the right frequency ranges.