My photo shows the roof of our school library in midday time. I think the physical aspect of this picture falls onto the relationship between the light and the shadow，or the so-called the rectilinear propagation of light, which is the basic principles for lots of other principles and experiments for example the pinhole imaging.
Since I was a little kid, I hace always been curious about the effect of light and shadow. It is that same curiosity that prompted me to take this picture of the roof of the school library. As the position of the sun changes in the sky, the roof cover will grow farther away from the sunlight, and the shadows spread even more. However, it is this magical time and position that was captured in this picture that creates the perfect relationship between the roof, the sunlight and shadow, like an object looking down to the water, with symmetrical but different shapes. The light and shadow effect also creates this spider-web shadow, which is also quite interesting. Of course, the glass also adds a different color to the picture, blocking some of the sunlight and avoiding the uncomfortable light of coming directly into the wall. Its existence makes the sunlight become softer and more soothing. This scene has deeply shocked my heart and I can not help to sigh at the uncanny combination of human and nature.