int led_Red = 11;
int led_Yellow = 10;
int led_Green = 9;

void setup() {}

void loop() {

  for(int i = 0 ; i <= 255 ; i++ ){

    analogWrite(led_Red, i);
    delay(10);
  }

  for(int i = 255 ;i>=0;i--){

    delay(10);
    analogWrite(led_Red, i);
  }

   for(int i = 0 ;i<=255;i++){

    delay(10);
    analogWrite(led_Yellow, i);
  }
  for(int i = 255 ;i>=0;i--){

    delay(10);
    analogWrite(led_Yellow, i);
  }

   for(int i = 0 ;i<=255;i++){

    delay(10);
    analogWrite(led_Green, i);
  }
  for(int i = 255 ;i>=0;i--){

    delay(10);
    analogWrite(led_Green, i);
  }

  for(int i = 0 ;i<=255;i++){

    delay(10);
    analogWrite(led_Yellow, i);
  }
  for(int i = 255 ;i>=0;i--){

    delay(10);
    analogWrite(led_Yellow, i);
  }

}