const int redPin = 9;    
const int greenPin = 10; 
const int bluePin = 11;  

void setup() {
  pinMode(redPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
  pinMode(bluePin, OUTPUT);
}

void loop() {
  // Turn on the red LED
  analogWrite(redPin, 255);
  analogWrite(greenPin, 0);
  analogWrite(bluePin, 0);
  delay(1000);

  // Turn on the green LED
  analogWrite(redPin, 0);
  analogWrite(greenPin, 255);
  analogWrite(bluePin, 0);
  delay(1000);

  // Turn on the blue LED
  analogWrite(redPin, 0);
  analogWrite(greenPin, 0);
  analogWrite(bluePin, 255);
  delay(1000);
}