#include <Adafruit_NeoPixel.h>

#define PIN 6
#define NUMPIXELS 16
Adafruit_NeoPixel ring = Adafruit_NeoPixel(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  // put your setup code here, to run once:
  ring.begin();
  ring.show();
}

void loop() {
  // put your main code here, to run repeatedly:
  rainbowCycle(5);
}

void rainbowCycle(int wait) {
  uint16_t i, j;

  for(j=0; j<256; j++) {
    for(i=0; i<ring.numPixels(); i++) {
      ring.setPixelColor(i, Wheel((i * 256 / ring.numPixels() + j) & 255));
    }
    ring.show();
    delay(wait);
  }
}

uint32_t Wheel(byte WheelPos) {
  WheelPos = 255 - WheelPos; 
  if(WheelPos < 85) {
    return ring.Color(255 - WheelPos * 3, 0, WheelPos * 3);
  } else if(WheelPos < 170) {
    WheelPos -= 85;
    return ring.Color(0, WheelPos * 3, 255 - WheelPos * 3);
  } else {
    WheelPos -= 170;
    return ring.Color(WheelPos * 3, 255 - WheelPos * 3, 0); 
  }
}