Addressable RGB LEDs such as the WS2812 have a built-in LED driver that allows the LEDs to be chained together and individually controlled. These LEDs are called “addressable” because instead of using a wire per color, each LED contains a small microchip that understands a special protocol sent over a single wire. The chip passes on the remaining data to the next LED, allowing them to be chained together. In this way, you can easily control the color of the individual LEDs.