int LED = 6 ;
int Brightness ;
int FadeAmount = 100 ;
void setup() {
  // put your setup code here, to run once:
pinMode(LED , OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
analogWrite(LED , Brightness);

Brightness = Brightness + FadeAmount ;

if (Brightness <= 0 || Brightness >= 255) {
  FadeAmount = -FadeAmount ;
}
delay(300);
}