// Define the pins for the LEDs
const int redLed = 7;
const int yellowLed = 4;
const int blueLed = 0;

void setup() {
  // Set the pins as outputs
  pinMode(redLed, OUTPUT);
  pinMode(yellowLed, OUTPUT);
  pinMode(blueLed, OUTPUT);
}

void loop() {
  // Turn on the red LED and turn off the others
  digitalWrite(redLed, HIGH);
  digitalWrite(yellowLed, LOW);
  digitalWrite(blueLed, LOW);

  // Wait for one second
  delay(1000);

  // Turn on the yellow LED and turn off the others
  digitalWrite(redLed, LOW);
  digitalWrite(yellowLed, HIGH);
  digitalWrite(blueLed, LOW);

  // Wait for one second
  delay(1000);

   // Turn on the blue LED and turn off the others
   digitalWrite(redLed, LOW);
   digitalWrite(yellowLed, LOW);
   digitalWrite(blueLed, HIGH);

   // Wait for one second
   delay(1000);
}