If you look through a prism at a bright rectangular form surrounded by a black background, images of the rectangle appear in in two differnet places.
Fig. 1 shows a photo with the image of the rectangular area on top and two different images below. These two images appear together in the prism. One image appears mirrored around the longitudinal axis (operation m), the second image does not appear mirrored, but with colored border spectra (operation b): red/yellow at the top and blue/turquoise at the bottom.
In Fig. 2 these two images are shown next to each other in the 2nd line. These two images were then viewed through a second prism, which was placed at a distance parallel to the first prism. The angle of the first prism remained unchanged. The distance and angle of the second prism were each adjusted in a such way, that operation m was followed by operation b and vice versa. The results are shown in the third line of Fig 2, which are amazing. It makes a big difference whether you apply operation m first and then operation b or vice versa. In mathematical terms this would mean that multiplying m times b produces something different than multiplying b times m. But the mathematical rule
m x b = b x m applies to numbers and things, not to processes. The result of this experiment shows that light cannot be viewed as being things (photons like small balls), but must be looked at as processes. This is in accord with Quantum physics, where photons are interpreted as processes.
I developed a graphic model, the so-called quantum model, which shows light as process. (see page light). To understand light it is also necessary to include processes in the eye and brain and mental processes of percieving*.
(see my video: Light, Quantum Physics and Buddhism).