#define RED 1
#define YELLOW 5
#define GREEN 9

void setup() {
    pinMode(RED, OUTPUT);
    pinMode(YELLOW, OUTPUT);
    pinMode(GREEN, OUTPUT);
}

void loop() {
    // Green light ON for 3 seconds
    digitalWrite(GREEN, HIGH);
    delay(3000);

    // Green OFF, Yellow ON for 0.5 seconds
    digitalWrite(GREEN, LOW);
    digitalWrite(YELLOW, HIGH);
    delay(500);

    // Yellow OFF, Red ON for 2 seconds
    digitalWrite(YELLOW, LOW);
    digitalWrite(RED, HIGH);
    delay(2000);

    // Yellow blinks (Red remains ON)
    digitalWrite(YELLOW, HIGH);
    delay(500);
    digitalWrite(YELLOW, LOW);

    // Red OFF, cycle repeats
    digitalWrite(RED, LOW);
}