const int redLEDPin = 9 ;
const int greenLEDPin = 10 ;
const int blueLEDPin = 11 ;

void setup()
{
}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(redLEDPin,HIGH) ;
  delay(2000) ;
  digitalWrite(redLEDPin,LOW) ;
  digitalWrite(greenLEDPin,HIGH) ;
  delay(2000) ;
  digitalWrite(greenLEDPin,LOW) ;
  digitalWrite(blueLEDPin,HIGH) ;
  delay(2000) ;
  digitalWrite(blueLEDPin,LOW) ;
}