// Constants for the LED pins
const int LED1 = 2;
const int LED2 = 3;
const int LED3 = 4;

void setup() {
  // Set the LED pins as outputs
    pinMode(LED1, OUTPUT);
      pinMode(LED2, OUTPUT);
        pinMode(LED3, OUTPUT);
        }

        void loop() {
          // Blink LED 1
            digitalWrite(LED1, HIGH);
              delay(400);
                digitalWrite(LED1, LOW);
                  delay(400);

                    // Blink LED 2
                      digitalWrite(LED2, HIGH);
                        delay(400);
                          digitalWrite(LED2, LOW);
                            delay(400);

                              // Blink LED 3
                                digitalWrite(LED3, HIGH);
                                  delay(400);
                                    digitalWrite(LED3, LOW);
                                      delay(400);
                                      }