#include <Adafruit_NeoPixel.h>
int PIN=12;
int N_LEDS=16;
Adafruit_NeoPixel ring = Adafruit_NeoPixel(N_LEDS,PIN);
void setup() 
{
  // put your setup code here, to run once:
  ring.begin();
}
void loop() 
{
  // put your main code here, to run repeatedly:
  for(int i=0; i<N_LEDS; i++)
  {
    ring.setPixelColor(i, ring.Color(0,0,255));
    ring.show();
    delay(100);
      if(i<8)
      {
        ring.setPixelColor(i, ring.Color(255,0,0));
        ring.show();
        delay(100);
      }
      else
      {
        ring.setPixelColor(i, ring.Color(0,255,0));
        ring.show();
        delay(100);
      }
  }
}