A Rainbow Line
You’ve probably seen around your house if you have some kind of crystal, a refraction of light. Sometimes this refraction of light lets you see all the colors on the spectrum also known as a rainbow. They usually come in splotches on your wall. This refraction of light is particularly unique.
This man must have a very prismatic window for a long, straight, precise line of a rainbow to shine through the window, onto his arm, creating this beautiful sight. This kind of refraction can usually only be made with a prism or a transparent optical element in the geometric shape of a triangle.