WS2812FX
WS2812 FX library for Arduino and ESP8266
...More complex effects can be created by dividing your string of LEDs into segments (up to ten) and programming each segment independently. Use the segment() function to program each segment's mode, color, speed, and direction (normal or reverse). Note, some effects make use of more than one color (up to three) and are programmed by specifying an array of colors. Random color introduced alternating from start and end of strip. Alternating white/red/black pixels running. Strobe effect with different strobe count and pause, controlled by speed setting. Classic Strobe effect. Cycling through the rainbow.