After trying some more angles, it seems "up" and "down" lighting makes the difference between "innies" and "outies", which hints the brain's interpretation of lights and shadows is in play here. "Left" or "right" doesn't seem to make a big difference.
After trying some more angles, it seems "up" and "down" lighting makes the difference between "innies" and "outies", which hints the brain's interpretation of lights and shadows is in play here. "Left" or "right" doesn't seem to make a big difference.