'Round and 'round the arrow goes, but where it points—nobody knows. As spotted by Sploid, this befuddling optical illusion of a spinning arrow appears to be pointing right no matter how many 180-degree turns you give it. See for yourself:

Right Pointing Arrow: spin this arrow 180 degrees and it still points to the right- only in a mirror will it point left (and only to the left). Another incredible ambiguous object illusion by mathematician Kokichi Sugihara of Meiji University in Japan, the inventor of this illusion and art form. A clever combination of reflection, perspective, and viewing angle produce this striking illusion. ➡️ Follow the link in my profile for info about where to get this illusion arrow and other amazing items featured here on @physicsfun #illusion #ambiguouscylinderillusion #ambiguouscylinder #geometry #mirrorreflection #physics #ambiguousobject #kokichisugihara #physicstoy #math #mathtoy #mathstoy #optics #opticalillusion #3dprinting #perspective #science #scienceisawesome

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The illusion was designed by Kokichi Sugihara, a mathematics professor at Meiji University in Japan. Sugihara is adept at creating 3D objects that seem to defy the laws of physics, using a “combination of reflection, perspective, and viewing angle” to trick viewers, according to the physicsfun Instagram page, which posted the video.

The effect still works when the object is held up to a mirror, although instead of pointing right, the reflection shows the arrow pointing left each time. The object appears symmetrical when viewed from above, but when you look at it head-on, it appears to come to a point on one side. It all comes down to the way the edge is carved—a testament not only to Sugihara's mathematical ability, but also his craftiness.

Want to see more of Sugihara’s work? In another video, a rack of cylinders appears to be transformed into a rack of rectangles right before your eyes.

[h/t Sploid]