A good optical illusion causes whole communities to worry and argue, and there is always some fundamental principle that exploits the difference in perception of information. It is often too difficult to understand, so Japanese psychologist Koski Takahashi developed a simple curvature-blindness test. He clearly shows why some people should not trust their eyes unconditionally.
Look at the picture with wavy lines. If you, like most people, see alternating smooth and angular lines on a gray background, and only smooth lines in the corners, then you have a pronounced "curvature blindness". This is not a defect, on the contrary, all the lines in this figure have the same bend angles. But under certain conditions, we stop perceiving their curvature, become "blind" to the truth and replace it with an interpretation from our imagination.
From this conclusion a logical question arises: why do we strive to see broken lines where they are not? Takahashi believes that this is a direct consequence of the evolution and anthropogenic nature of the human environment. In nature, there are few geometrically correct, clear lines, but there are many of them among man-made things - our consciousness has adapted to see the markers of this human world and navigate by them.
Naval aviation pilots are well aware that it is almost impossible to visually orientate themselves in height and distance above the water when looking at the waves or the horizon. The eyes instinctively seek a clear, prominent landmark - a buoy, a ship's mast, a rocky silhouette, etc. On the basis of these factors, identification marks or, on the contrary, means of camouflage on the ground are being created today. Please note that in the dough, the light and dark parts of the lines are positioned differently to emphasize the curvature of the bend. And this is also part of the illusion, with the help of which one can manipulate the viewer's consciousness.