void setup() {  // initialize digital pin 13 as an output.
   pinMode(13, OUTPUT);
   pinMode(12, OUTPUT);
   pinMode(11, OUTPUT);
}

// the loop function runs over and over again forever

void loop() {
   digitalWrite(13, HIGH); // turn the LED on (HIGH is the voltage level)
   delay(200); // wait for a second
   digitalWrite(13, LOW); // turn the LED off by making the voltage LOW
   delay(200); // wait for a second

   digitalWrite(12, HIGH); // turn the LED on (HIGH is the voltage level)
   delay(300); // wait for a second
   digitalWrite(12, LOW); // turn the LED off by making the voltage LOW
   delay(300); // wait for a second

   digitalWrite(11, HIGH); // turn the LED on (HIGH is the voltage level)
   delay(400); // wait for a second
   digitalWrite(11, LOW); // turn the LED off by making the voltage LOW
   delay(400); // wait for a second
}