Parabola and car (head) lights
Explore how the geometric properties of a parabola are used in car lights, that is how beams from the yellow point source reflect... (further reading)
Compare the bellow pictures, which indicate high-beam (flash lights) and low-beam (dimmed lights) ... and think what this has to do with the 'shape of car's headlight bulb'.
D.Kobal with GeoGebra
See some other nice examples.