Often searching out the graphical symmetry in chaos, while still maintaining the personality.
Same story happens in a photo camera. I am now probably risking to get a negative evaluation of my physics knowledge, which would unfortunately be quite fair… However, although the physical reasons might differ, the conceptual comparison seems to be quite adequate. When shooting with a photo camera, you let the sensor see the scene through a hole in the lens called aperture. The larger this hole is, the more light reaches the sensor. Normally the sensor is closed by a curtain called shutter. When shooting, the shutter opens, light reaches the sensor through the aperture hole, and then it closes again. The longer the opening lasts, the more light reaches the sensor. This time is called shutter speed.