As Can be observed during the image, the LED image system is made of a diode symbol with two arrows. The two arrows denote that light is emitted from this gadget. An LED has an anode and cathode terminal. While in the picture, the anode is over the still left https://www.uk-exhibitionstands.co.uk/product/monolith-4-6m-display-wall-4-6x2-4/