// activity 2 - Make LED flash
int led1 = 11;  // LED 1 is attached to pin 11

void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(led1, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(led1, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for 1000 milliseconds
  digitalWrite(led1, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);                       // wait for 1000 milliseconds
}