int redLight = 12;
int greenLight = 10;
int yellowLight = 8;

int yellowLightDelay = 3 * 1000 ;// 6 seconds 
int lightDelay = 6 * 1000 ;// 10 seconds

void setup() {
  pinMode(redLight , OUTPUT);
  pinMode(greenLight , OUTPUT);
  pinMode(yellowLight , OUTPUT);
}

void loop() {
  //turning the red light on / off
  digitalWrite(redLight , HIGH);
  delay(lightDelay);
  digitalWrite(redLight , LOW);
  
  digitalWrite(yellowLight , HIGH);
  delay(yellowLightDelay);
  digitalWrite(yellowLight , LOW);
 
  digitalWrite( greenLight , HIGH);
  delay(lightDelay);
  digitalWrite(greenLight , LOW);

  digitalWrite(yellowLight , HIGH);
  delay(yellowLightDelay);
  digitalWrite(yellowLight , LOW);


}