int leftPin = 3;                // LED connected to digital pin 13
 int rightPin = 11;                // LED connected to digital pin 13

 void playNote() {
   for (int i=0; i < 100; i++) {
     digitalWrite(leftPin, HIGH);   // sets the LED on
     digitalWrite(rightPin, HIGH);   // sets the LED on
     delay(1);                  // waits for a second
     digitalWrite(leftPin, LOW);    // sets the LED off
     delay(1);                  // waits for a second
     digitalWrite(leftPin, HIGH);   // sets the LED on
     digitalWrite(rightPin, LOW);   // sets the LED on
     delay(1);                  // waits for a second
     digitalWrite(leftPin, LOW);    // sets the LED off
     delay(1);                  // waits for a second
   }
 }

 void setup()                    // run once, when the sketch starts
 {
   pinMode(leftPin, OUTPUT);      // sets the digital pin as output
   pinMode(rightPin, OUTPUT);      // sets the digital pin as output
 }

 void loop()                     // run over and over again
 {
   playNote();
   delay(200);
 }