A typical Arduino Uno prototyping scenario.
First of all, we see the Arduino Uno in the lower-left-hand corner of the image. A little to the right, we see a stick of eight WS2812B tricolor LEDs (commonly known as “NeoPixels” because that’s what the folks at Adafruit call them). In addition to red, green, and blue sub-LEDs, these little scamps also contain three 8-bit pulse-width modulators (PWMs), thereby allowing each NeoPixel to display 2^8 * 2^8 * 2^8 = 2^24 = 16,777,216 different colors. Also, these little rascals are daisy-chained together, which means we can drive the whole stick using a single digital output from the Arduino Uno.