int ledPIN1 = 0;
int ledPIN2 = 4;
int ledPIN3 = 16;
int ledPIN4 = 17;
void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  Serial.println("Hello, ESP32!");
  pinMode(ledPIN1, OUTPUT);
  pinMode(ledPIN2, OUTPUT);
  pinMode(ledPIN3, OUTPUT);
  pinMode(ledPIN4, OUTPUT);
}

void loop() {
  digitalWrite(ledPIN1, HIGH);
  delay(500); // this speeds up the simulation
  digitalWrite(ledPIN1, LOW);
  delay(500);
  digitalWrite(ledPIN2, HIGH);
  delay(500); // this speeds up the simulation
  digitalWrite(ledPIN2, LOW);
  delay(500);
  digitalWrite(ledPIN3, HIGH);
  delay(500); // this speeds up the simulation
  digitalWrite(ledPIN3, LOW);
  delay(500);
  digitalWrite(ledPIN4, HIGH);
  delay(500); // this speeds up the simulation
  digitalWrite(ledPIN4, LOW);
  delay(500);
}