designer's own words:The yellow light switch have you ever tried to turn on and off all of the light switch as you don’t know which one is which light? the buttons of existing light switch are same shape so it has a problem to recognize which one is. because on that, some of the people tend to write the importation about switch on the button. the product is designed to recognize the information about the button. This light switch turns on one of the yellow light if you touch the image of light bulb.