Just in case you are wondering about this image, it is something that only a math/science nerd would appreciate. One day, I left a roll of reflective Mylar on the window sill of my classroom. Later on, I found this arc projected onto the ceiling. A strong, narrow beam of sunlight had come through the window and reflected off of the cylindrical roll of Mylar, and the reflected light became this arc when it hit the ceiling. I consulted several math teachers, and we all agreed that this is half of a hyperbola (in wider pictures, you can see the asymptotic behavior near the ends). Several of them suggested that we could use the ceiling tiles as a coordinate plane and compute the formula, although none of us bothered to do so. However, I took several pictures from different angles, resulting in the images you see throughout this site.