void setup (){ 
  pinMode(9, OUTPUT); 
} 
void loop (){
  analogWrite (9,64);
  delay (1000);
  analogWrite (9,127);
  delay (1000);
  analogWrite (9,191);
  delay (1000);
  analogWrite (9,255);
  delay (1000);
  analogWrite (9,0);
  delay (1000);
}