//define Global variables
const int LEDpin = 11; //set LED pin 
int time = 5;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(LEDpin, OUTPUT); 
}

void loop() {
  // put your main code here, to run repeatedly:
  for (int i=0;i<256;i++){
    analogWrite(LEDpin,i);
    delay(time);
  }
  for (int i=255;i>0;i--){
    analogWrite(LEDpin,i);
    delay(time);
  }
}
//this was correct, well done !!