const int ledPin1 = 2;  // Connect LED 1 to digital pin 2
const int ledPin2 = 3;  // Connect LED 2 to digital pin 3
const int ledPin3 = 4;  // Connect LED 3 to digital pin 4

void setup() {
  pinMode(ledPin1, OUTPUT);
    pinMode(ledPin2, OUTPUT);
      pinMode(ledPin3, OUTPUT);
      }

      void loop() {
        digitalWrite(ledPin1, HIGH); // Turn on LED 1
          delay(1000);                  // Wait for 1 second
            digitalWrite(ledPin1, LOW);  // Turn off LED 1
              delay(1000);                  // Wait for 1 second

                digitalWrite(ledPin2, HIGH); // Turn on LED 2
                  delay(1000);                  // Wait for 1 second
                    digitalWrite(ledPin2, LOW);  // Turn off LED 2
                      delay(1000);                  // Wait for 1 second

                        digitalWrite(ledPin3, HIGH); // Turn on LED 3
                          delay(1000);                  // Wait for 1 second
                            digitalWrite(ledPin3, LOW);  // Turn off LED 3
                              delay(1000);                  // Wait for 1 second
                              }