void setup() {
  int ld = 13;
  while (ld > 3) {
    pinMode(ld, OUTPUT);
    ld = ld - 1;
  }
}

void loop() {
  int ld = 13;
  while (ld > 3) {
    digitalWrite(ld, HIGH);
    delay(180);
    digitalWrite(ld, LOW);
    ld = ld - 1;
  }
  while (ld <14) {
    digitalWrite(ld, HIGH);
    delay(180);
    digitalWrite(ld, LOW);
    ld = ld + 1;
  }
}