Shadow is an optical phenomenon. When light cannot pass through opaque objects, it forms a dark area around a particular object. The part that light cannot reach is called the shadow. Since the light travels in straight lines in the same uniform medium, the shadows of the columns are projected onto the ground. There is more light around the shadow than in the shadow, making the surrounding area appear brighter. The difference in the amount of light allows the eye to distinguish between shadows and surrounding areas. The length of the shadow is related to the Angle of the light source, and the direction of the shadow is opposite to that of the light source. That's why the shadow on the left pillar is longer and the shadow on the right pillar is shorter.
On the right, there are two rainbows. A rainbow is formed when white light passes through some transparent Windows. It splits into seven constituent colors. This splitting of white light is called dispersion. Depending on the frequency of the monochromatic light, different media cause each beam to have a different speed. Red has the longest wavelength and the lowest frequency, it's at the top of the rainbow, while purple has the shortest wavelength and the fastest frequency, so it's at the bottom of the rainbow. So we get seven different colors of sunlight.