void setup() {
  // turn light on for 10 seconds, then off for 5 seconds :
  pinMode(13, OUTPUT);
  digitalWrite(13, HIGH);
  delay(1000); 
  digitalWrite(13, LOW);
  delay(1000);
}

void loop() {
  // turns light on for 1 second, then off for 1 second, then repeats
  digitalWrite(13, LOW);
  delay(1000);
  analogWrite(13, 0);
  delay(500);
  analogWrite(13, 15);
  delay(500);
  analogWrite(13, 120);
  delay(500);
  analogWrite(13, 255);
  delay(500);
  analogWrite(13, 120);
  delay(500);
  analogWrite(13, 15);
  delay(500); 
}