void setup() {
  Serial.begin(115200);
  pinMode(25, OUTPUT);
  pinMode(26, OUTPUT);
  pinMode(27, OUTPUT);
  pinMode(2, INPUT);
}

void loop() {
  int switchState = digitalRead(2);

  if (switchState == 1) {
    Serial.println("Started");

    digitalWrite(25, HIGH);
    delay(500);
    digitalWrite(25, LOW);
    delay(500);

    digitalWrite(26, HIGH);
    delay(500);
    digitalWrite(26, LOW);
    delay(500);

    digitalWrite(27, HIGH);
    delay(500);
    digitalWrite(27, LOW);
    delay(500);

    Serial.println("Ended");
  } else {
    digitalWrite(25, LOW);
    digitalWrite(26, LOW);
    digitalWrite(27, LOW);
  }

  delay(1000);
}