This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
PSM Optical illusion with decorative patterns. en Optical illusion with decorative patterns archive org Popular Science Monthly Volume Jastrow Joseph The Mind's Eye author PDold PDUS Uploaded with Popular Science Monthly illustrations Optical illusions
Page 2023 Free-images.com. All images are Public Domain