void setup()
 {
  pinMode (11,OUTPUT);
 }

 
 void loop ()
 {
 for(int x=0;x<256;x=x+85)
 {
  analogWrite(11,x);
  delay(100);
 }
 for(int x=255;x>0;x=x-5)
 {
  analogWrite(11,x);
  delay(100);
 }
 }