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

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

void loop() {
  t_blink(80);
}

void t_blink(int t) {
  for (int i = 0; i < numLEDs; i++) {
    digitalWrite(leds[i], HIGH);
    delay(t);
  }
  for (int i = 0; i < numLEDs; i++) {
    digitalWrite(leds[i], LOW);
    delay(t);
  }
}