Fade an LED Off to On to Off

// =================================================
// Fade an LED off to on to off
// =================================================

const int LED = 9;          // LED pin
const int max = 128;        // maximum brightness (255 max)
int i;                      // loop counter

void setup()
{
   pinMode(LED,OUTPUT);     // LED pin is output
}

void loop()
{
   for (i = 0; i <= max; i++)
   {
      analogWrite(LED,i);  // set LED brighness
      delay(10);           // pause (milliseconds)
   }
   
   for (i = max; i >= 0; i--)
   {
      analogWrite(LED,i);  // set LED brighness
      delay(10);           // pause (milliseconds)
   }
}