int jumlahlampu = 10;

int LEDKU[] = {13, 12, 11, 10, 9, 8, 7, 6, 5, 4};

void setup() 
{
  for (int i=0; i<jumlahlampu; i++)
  {
    pinMode(LEDKU[i], OUTPUT);
  }
}

void loop() 
{
  for (int l = 0; l<10; l++)
  {
    digitalWrite(LEDKU[l], HIGH);
    delay(500);
    digitalWrite(LEDKU[l], LOW);
  }
  
  for (int l = 9; l>0; l--)
  {
    digitalWrite(LEDKU[l], HIGH);
    delay(500);
    digitalWrite(LEDKU[l], LOW);
  }
}