// https://learn.sparkfun.com/tutorials/sparkfun-inventors-kit-experiment-guide---v41/circuit-1a-blink-an-led
int led = LED_BUILTIN; //13

void setup() {
  // put your setup code here, to run once:
  pinMode(led, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(led, HIGH);
  delay(2000);
  digitalWrite(led, LOW);
  delay(2000);
}