int yellowLedPin = 9;
//-------------------------------------------------------------------
void setup() {

  pinMode(yellowLedPin, OUTPUT);
}
//-------------------------------------------------------------------
void loop() {
  delay(1000);
  for (int brightness = 0; brightness < 256; brightness++) {
    analogWrite(yellowLedPin, brightness);
    delay(10);
  }
  delay(1000);
  for (int brightness = 255; brightness > -1; brightness--) {
    analogWrite(yellowLedPin, brightness);
    delay(10);
  }
}