int led = 6;
int bri = 0;
int fad = 5;

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

void loop() {
  
  analogWrite(led, bri);
  bri += fad;
  if (bri <= 0 || bri >= 255) {
    fad = -fad;
  }
  delay(60);
}