int REDLED= 9;
int YELLOWLED= 10;
int GREENLIGHT= 11;

void setup() {
 pinMode(REDLED, HIGH);
 pinMode(YELLOWLED, HIGH);
 pinMode(GREENLIGHT, HIGH);
}

void loop() {
digitalWrite(REDLED, HIGH);
delay(1000);
digitalWrite(REDLED, LOW);
delay(1000);
digitalWrite(YELLOWLED, HIGH);
delay(1000);
digitalWrite(YELLOWLED, LOW);
delay(1000);
digitalWrite(GREENLIGHT, HIGH);
delay(1000);
digitalWrite(GREENLIGHT, LOW);
delay(1000);
}