Mirror, Mirror On The Wall, Do My Eyes Deceive Me After All

Say what you will about illusions, [Create Inc] has some 3D prints that appear to change shape when viewed in a mirror. For example, circles transform into stars and vice versa. A similar trick was performed by [Kokichi Sugihara] in 2016, where he showed circles that appear as squares in the mirror. For the trick to work, the camera’s position (or your eye) is important as the shapes look different from different angles. The illusion comes in when your brain ignores any extra information and concludes that a much more complex shape is a simpler one. [Create Inc] walks you through the process of how the illusion works and how it was created in Blender.

When he posted the video on Reddit, most seemed to think that it wasn’t a mirror and there was some camera trickery. At its heart, this is reverse-engineering a magic trick, and we think it’s an impressive one. STL files are on Thingiverse or Etsy if you want to print your own. We covered a second illusion that [Kokichi] did that relies on a similar trick.

Continue reading “Mirror, Mirror On The Wall, Do My Eyes Deceive Me After All”

Dancing Arrows To Break Your Brain

Last year, mathematician and professional optical illusionist [Kokichi Sugihara] came up with an arrow that only points one way. Technically, it’s ‘anomalous mirror symmetry’, but if you print this arrow and look at it juuuussst right, it appears this arrow only points one way.

[Ali] had the idea to turn this arrow illusion into something motorized, and for that he turned to 3D printing. The models for the illusion arrows were already available, but there had to be a way to turn a single arrow into an art installation. For that, you just need a few 9g servos. [Ali] slightly modified his servos so they would turn a full 180 degrees, and designed a magnetic mount to allow easy swap-out of these arrows.

The servos are attached to a 3D printed frame with heat-staked threaded inserts, and driven by a Pololu servo driver. The effect is great, with multiple arrows twisting and turning but still only appearing to point to the right. [Ali] put together two videos of this arrow illusion, one that’s effectively a build guide, and of course all the STLs are available in a link in the description.

Continue reading “Dancing Arrows To Break Your Brain”