// the setup function runs once when you press reset or power the board
const int ledPin = 3;    // the number of the LED pin

// variables will change:
int buttonState;  // variable for reading the pushbutton status
 
  void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(ledPin, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(ledPin, HIGH);  // turn the LED on (HIGH is the voltage level)
  delay(100);                      // wait for a second
  digitalWrite(ledPin, LOW);   // turn the LED off by making the voltage LOW
  delay(300);                      // wait for a second
}