int ledPin = 2;    
void setup() 
{
  pinMode(ledPin, OUTPUT);
}
void loop()
 {
for (int fadeValue = 0 ; fadeValue <= 1023; fadeValue += 35) {
analogWrite(ledPin, fadeValue);
delay(10);
  }
for (int fadeValue = 1023 ; fadeValue >= 0; fadeValue -= 35) {
analogWrite(ledPin, fadeValue);
delay(10);
  }
}