void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(25, OUTPUT);
  pinMode(27, OUTPUT);
  pinMode(13, OUTPUT);
  pinMode(23, OUTPUT);
  pinMode(21, OUTPUT);
  pinMode(4, OUTPUT);
}

void loop() {
  digitalWrite(25, HIGH);
  digitalWrite(27, LOW);
  digitalWrite(13, LOW);
  digitalWrite(23, LOW);
  digitalWrite(21, LOW);
  digitalWrite(4, HIGH);
  delay(3000);
  digitalWrite(25, LOW);
  digitalWrite(27, HIGH);
  digitalWrite(13, LOW);
  digitalWrite(23, LOW);
  digitalWrite(21, HIGH);
  digitalWrite(4, LOW);
  delay(3000);
  digitalWrite(25, LOW);
  digitalWrite(27, LOW);
  digitalWrite(13, HIGH);
  digitalWrite(23, HIGH);
  digitalWrite(21, LOW);
  digitalWrite(4, LOW);
  delay(3000);
  digitalWrite(25, LOW);
  digitalWrite(27, HIGH);
  digitalWrite(13, LOW);
  digitalWrite(23, LOW);
  digitalWrite(21, HIGH);
  digitalWrite(4, LOW);
  delay(3000);
}