int ledPin = 16;
int ledPin2 = 4;
int ledPin3 = 2;
int ledPin4 = 15;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(ledPin, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  pinMode(ledPin3, OUTPUT);
  pinMode(ledPin4, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
 digitalWrite(ledPin, HIGH);
 digitalWrite(ledPin2, HIGH);
 digitalWrite(ledPin3, HIGH);
 digitalWrite(ledPin4, HIGH);
 delay(2000);
 delay(2000);
 delay(2000);
 delay(2000);
 digitalWrite(ledPin, LOW);
 digitalWrite(ledPin2, LOW);
 digitalWrite(ledPin3, LOW);
 digitalWrite(ledPin4, LOW);
 delay(2000);
  delay(2000);
  delay(2000);
  delay(2000);

}