#include <Adafruit_NeoPixel.h>  //Library
int PIN =12;
int N_LEDS =16; //Because we have 16 LEDs in the NeoPixel Ring.

Adafruit_NeoPixel ring = Adafruit_NeoPixel(N_LEDS, PIN);
//ring is variable(Adafruit_NeoPixel library) which is used to store the number of LEDs
// in the NeoPixel ring and pin number of NeoPixel Ring which is connected to the arduino.

void setup() 
{
  ring.begin();  //Start functionality like glowing rings LEDs
}

void loop()
 {
  for(int i=0; i<N_LEDS; i++ ) //repeats 16 times 
  {
    ring.setPixelColor(i , ring.Color(0, 0, 255)); // change color of each LED in blue
    ring.show();
    delay(500); 
  }
 }