This is a video demonstration (below, above is a static image unless you do a bat-spin) of a 3-D arrow optical illusion that always appears to point right when turned in 180-degree increments (and viewed from the proper angle). In the demonstration, mathematician (and the arrow's creator) Kokichi Sugihara eventually picks the thing up so you can see how it works, which kind of made my brain hurt. "You sure that's not the ice cream sandwich I just watched you try to eat in one bite?" What? "Brain freeze." Huh? "Brain freeze." Huh? "Brain freeze." Huh? "Brain fr-- oh I get it." *wink*
Keep going for the video.
Thanks to Marco with the cat, who -- okay, which one of you just hissed at me?