// the number of the LED pin
const int ledR = 4;  // 16 corresponds to GPIO16
const int ledG = 16;
const int ledB = 17;



void setup() {
  // set the LED as an output
  pinMode(ledR, OUTPUT);
  pinMode(ledG, OUTPUT);
  pinMode(ledB, OUTPUT);
}

void loop(){
  // increase the LED brightness
  for(int dutyR = 0; dutyR <= 255; dutyR++){   
    // changing the LED brightness with PWM
    analogWrite(ledR, dutyR);
    delay(15);
  }

  // increase the LED brightness
  for(int dutyG = 0; dutyG <= 255; dutyG++){   
    // changing the LED brightness with PWM
    analogWrite(ledG, dutyG);
    delay(15);
  }

  // increase the LED brightness
  for(int dutyB = 0; dutyB <= 255; dutyB++){   
    // changing the LED brightness with PWM
    analogWrite(ledB, dutyB);
    delay(15);
  }

  // decrease the LED brightness
  for(int dutyB = 255; dutyB >= 0; dutyB--){
    // changing the LED brightness with PWM
    analogWrite(ledB, dutyB);
    delay(15);
  }


  // decrease the LED brightness
  for(int dutyG = 255; dutyG >= 0; dutyG--){
    // changing the LED brightness with PWM
    analogWrite(ledG, dutyG);
    delay(15);
  }

  // decrease the LED brightness
  for(int dutyR = 255; dutyR >= 0; dutyR--){
    // changing the LED brightness with PWM
    analogWrite(ledR, dutyR);
    delay(15);
  }
}