CODE #2 (ISTE 2016)

void setup() {

  pinMode(10, OUTPUT);
  //pin 10 is a PWM pin which can take steps from 0-255

   digitalWrite(10, LOW);
  //turn LED off
}

void loop() {

  int x;
  for (x=0; x<= 255; x=x+1) {
    analogWrite(10, x);
    delay(10);

  }//step up brightness

  for (x=255; x>=0; x=x-1)  {
    analogWrite(10,x);
    delay(10);
  }//step down brightness

}