int buttonPin = 2;  // Input pin for the button
int ledPin = 13;    // Output pin for the LED

void setup() {
  pinMode(buttonPin, INPUT);  // Set button pin as input
  pinMode(ledPin, OUTPUT);    // Set LED pin as output
}

void loop() {
  int buttonState = digitalRead(buttonPin);  // Read the button state
  while (buttonState == LOW) {
    // Blink the LED while the button is NOT pressed
    digitalWrite(ledPin, HIGH);
    delay(500);
    digitalWrite(ledPin, LOW);
    delay(500);

    buttonState = digitalRead(buttonPin);  // Recheck the button state in each loop iteration
  }
}