const int ledPins[] = {13, 12, 11, 10, 9}; // pin LED
const int numLeds = sizeof(ledPins) / sizeof(ledPins[0]);
const int buttonPin = 2; // pin push button
int ledState = LOW;
int buttonState;
int lastButtonState = LOW;
unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 50;

void setup() {
  for (int i = 0; i < numLeds; i++) {
    pinMode(ledPins[i], OUTPUT);
  }
  pinMode(buttonPin, INPUT);
}

void loop() {
  int reading = digitalRead(buttonPin);

  if (reading != lastButtonState) {
    lastDebounceTime = millis();
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {
    if (reading != buttonState) {
      buttonState = reading;

      if (buttonState == HIGH) {
        ledState = !ledState;

        if (ledState == HIGH) {
          for (int i = 0; i < numLeds; i++) {
            digitalWrite(ledPins[i], HIGH);
            delay(250);
            //digitalWrite(ledPins[i], LOW);
          }
        } else {
          for (int i = 0; i < numLeds; i++) {
            digitalWrite(ledPins[i], LOW);
            //delay(250);
            //digitalWrite(ledPins[i], HIGH);
            //delay(250);
          }
          for (int i = numLeds - 1; i >= 0; i--) {
            digitalWrite (ledPins[i], HIGH);
            delay(250);
          }
        }
      }
    }
  }

  lastButtonState = reading;
}