// Define a boolean variable
bool ledOn = false  ;

void setup() {
  // Initialize digital pin 13 as an output
  pinMode(13, OUTPUT);
}

void loop() {
  // Toggle the value of the boolean variable
  ledOn = !ledOn;

  // Set the state of digital pin 13 based on the boolean variable
  digitalWrite(13, ledOn);

  // Wait for 1 second
  delay(1000);
}