int Green_LED = 18;
int Yellow_LED = 19;
int Red_LED = 23;

void setup() { // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(Green_LED, OUTPUT);
  pinMode(Yellow_LED, OUTPUT);
  pinMode(Red_LED, OUTPUT);
}

void loop() { // codes in loop() runs forever
  digitalWrite(Green_LED, LOW);
  delay(500); //this speeds up the simulation
    digitalWrite(Yellow_LED, LOW);
  delay(500); //this speeds up the simulation
    digitalWrite(Red_LED, LOW);
  delay(500); //this speeds up the simulation
    digitalWrite(Green_LED, HIGH);
  delay(500); //this speeds up the simulation
  digitalWrite(Yellow_LED, HIGH);
  delay(500); //this speeds up the simulation
  digitalWrite(Red_LED, HIGH);
  delay(500); //this speeds up the simulation
}