Тут и анаморфные картинки, и каустки, и все на свете:))
Mitchell Feigenbaum discovered an intriguing property of viewing images through cylindrical mirrors or looking into water. Because the eye is a lens with an opening of about 5mm, many different rays of reflected images reach the eye, and need to be interpreted by the visual system. This has the surprising effect that what one perceives depends on the orientation of the head, whether it is tilted or not. I explain and illustrate this phenomenon on the example of a human eye looking at a ruler immersed in water.
Comments: Accepted for American Journal of Physics
Frequency-dependent capacitors using paper: https://arxiv.org/abs/2105.05877
Bart H. McGuyer
Measurements of capacitors made with paper sheets reveal a significant decrease in capacitance with increasing frequency from 10 to 100,000 Hz, offering a simple demonstration of complex dielectric phenomena using common equipment.
Comments: 3 pages, 2 figures
Journal reference: American Journal of Physics 89, 370 (2021)