he clock consists of a RGB LED matrix where both digits for the hours are superimposed in red and blue, i.e. the LEDs which are shared by both digits light up in purple. Similarly the digits from the minutes are shown below also superimposed. When the diffraction grating is placed in front of the LED matrix the red and blue dots get separated because they are diffracted at different angles. In this way the time becomes readable. As a twist I also molded a diffraction grating onto the 3D printed holder of the screen making it shimmer in a rainbow pattern.