const int ledDelay = 5000;
const int redPin = 10;
const int yellowPin = 9;
const int greenPin = 8;

void setup() {
    pinMode(redPin, OUTPUT);
    pinMode(yellowPin, OUTPUT);
    pinMode(greenPin, OUTPUT);
}

void loop() {
    digitalWrite(redPin, HIGH);
    delay(ledDelay);
    digitalWrite(yellowPin, HIGH);
    delay(2000);
    digitalWrite(greenPin, HIGH);

    digitalWrite(redPin, LOW);
    digitalWrite(yellowPin, LOW);
    delay(ledDelay);
    digitalWrite(yellowPin, HIGH);
    digitalWrite(greenPin, LOW);
    delay(2000);
    digitalWrite(yellowPin, LOW);
}