int LED = 12;	            // tell Arduino that pin 12 is going to be called “LED” for the following sketch

void setup() {

      for (int i = 8; i <= 13; i++) {
        pinMode(i, OUTPUT);   // initialise all the LEDs in a loop one at a time
      }

}

void loop() {	            // the loop function runs over and over again forever

      for (int i = 8; i <= 13; i++) {
        digitalWrite(i, HIGH);    //turn on each LED one at a time
        delay(200);
        digitalWrite(i, LOW);     //turn off each LED one at a time
        delay(200);
      }
}