#include <Adafruit_NeoPixel.h>

#define PIN 6
#define NUMPIXELS 8

Adafruit_NeoPixel pixels(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  pixels.begin();
  pixels.show();
}

void loop() {
  rainbow(20);
}

void rainbow(int wait) {
  for (long firstPixelHue = 0; firstPixelHue < 5*65536; firstPixelHue += 256) {
    for (int i = 0; i < NUMPIXELS; i++) {
      int pixelHue = firstPixelHue + (i * 65536L / NUMPIXELS);
      pixels.setPixelColor(i, pixels.gamma32(pixels.ColorHSV(pixelHue)));
    }
    pixels.show();
    delay(wait);
  }
}