Each of the lenticular pieces depicted below is actually a combination of two photos, interlaced together digitally. By attaching a special lens to the front of each print, the image switches between the two photos, creating the illusion of the lights flickering on and off as the viewing angle changes. This of course only works when seeing the pieces in person, but the moving example below helps demonstrate the created effect. In person, it is a much more subtle switching between the lit and unlit images - the prints appear to shine with an inner light.
