int pins[10] = {23, 22, 19, 18, 5, 17, 16, 4, 0, 2};


void setup() {
  // put your setup code here, to run once:
  for (int i = 0; i < 10; i++) {
    pinMode(pins[i], OUTPUT);
    digitalWrite(pins[i], LOW);
  }
}

void loop() {
  int index = 0;
  while (true) {
    digitalWrite(pins[index], HIGH);
    digitalWrite(pins[(index + 9) % 10], LOW);
    index += 1;
    delay(1000); // this speeds up the simulation
  }
}