#include <Adafruit_NeoPixel.h>
int pin =12;
int N_LEDS=40;
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(0,0,0));
  ring.show();
  delay(500);

  if(i<10)
  {
  ring.setPixelColor(i,ring.Color(255,0,0));
  ring.show();
  delay(500);
  }

  else if(i>=10;i<20){
   ring.setPixelColor(i,ring.Color(0,255,0));
   ring.show();
   delay(500);  
  }
   else  if(i>=20;i<30){
   ring.setPixelColor(i,ring.Color(0,0,255));
   ring.show();
   delay(500);  
  }
   else{
   ring.setPixelColor(i,ring.Color(0,0,0));
   ring.show();
   delay(500);  
  }
}
}