void setup() {
  pinMode(13, OUTPUT);
}

void loop() {
  digitalWrite(13, LOW);
}

void setup() {
  pinMode(13, OUTPUT);
}

void loop() {
  digitalWrite(13, HIGH);
}

void setup() {
  pinMode(13, INPUT);
}

void loop() {
  digitalWrite(13, HIGH);
}

void setup() {
  pinMode(13, INPUT_PULLUP);
}

void loop() {
  digitalWrite(13, HIGH);
}