void setup() {
  pinMode(0, OUTPUT);
  pinMode(1, OUTPUT);
  pinMode(13, OUTPUT);   // set the digital pin as output

}

void loop() {
  digitalWrite(0, HIGH); // turn on led
  delay(500);            // delay for 1000 ms
  digitalWrite(1, HIGH); // turn on led
  digitalWrite(0, LOW);   // turn off led
  delay(500);
  digitalWrite(13, HIGH);
  digitalWrite(1, LOW);  // turn off led
  delay(500);            // delay for 1000 ms
  digitalWrite(13, LOW);
  delay(500);
}