Optical Illusion Pen Holder – Round or Square?

This pen holder is based on the fascinating work of Kokichi Sugihara, known for his mind-bending optical illusions, and inspired by the original STL model from Dandy Cat Lab.

I remixed their design to create this functional version: depending on the viewing angle, the holder appears either perfectly round or perfectly square.

It’s not just a pen holder – it’s also a fun conversation piece for your desk!

🔹 Remix of the base model by Dandy Cat Lab

🔹 Optical illusion concept by Kokichi Sugihara

🔹 Printed version adapted as a practical pen holder

Download it, print it, and enjoy the surprise effect when you turn it around.