void setup() {
  // put your setup code here, to run once:
  pinMode(4, OUTPUT);
  pinMode(13, OUTPUT);
  pinMode(18, OUTPUT);
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
}

void loop() {
  // put your main code here, to run repeatedly:
  delay(1000); // this speeds up the simulation
  digitalWrite(4, HIGH);
  digitalWrite(13, LOW);
  digitalWrite(18, HIGH);
  delay(1000);
  digitalWrite(4, LOW;)
  digitalWrite(13, HIGH);
  digitalWrite(18, LOW);
  delay(1000);

}