int brightness = 0;
boolean dimming = 0;
void setup() {
  // put your setup code here, to run once:
  pinMode(12, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  if(dimming){
    brightness--;
    analogWrite(12, brightness);
    Serial.println(brightness);
    if(brightness < 5){
      dimming = !dimming;
    }
  } else {
    brightness++;
    Serial.println(brightness);
    analogWrite(12, brightness);

    if(brightness > 250){
      dimming = !dimming;
    }
  }
}