const int switchPin = 13;    // Connect the push button to digital pin 13
const int ledPins[] = {23, 22, 21, 4};  // Connect the LEDs to digital pins 23, 22, 21, and 4
const int numLeds = sizeof(ledPins) / sizeof(ledPins[0]);  // Calculate the number of LEDs

bool buttonState = false;   // variable to store the state of the push button
bool lastButtonState = false;   // variable to store the previous state of the push button
int ledState = 15;   // variable to store the LED pattern, starts from 15 (binary: 1111)

void setup() {
  pinMode(switchPin, INPUT_PULLUP); // Enable internal pull-up resistor for the push button
  for (int i = 0; i < numLeds; i++) {
    pinMode(ledPins[i], OUTPUT);    // Set LED pins as OUTPUTs
  }
  updateLeds(); // Initially update LEDs based on the initial ledState
}

void loop() {
  buttonState = digitalRead(switchPin);

  // Check if the button state has changed
  if (buttonState != lastButtonState) {
    // If the new state is LOW (pressed), decrement the LED pattern
    if (buttonState == LOW) {
      if (ledState > 0) {
        ledState--; // Decrement the LED pattern
        updateLeds(); // Update LEDs based on the new ledState
      }
    }
    // Save the current button state for comparison in the next iteration
    lastButtonState = buttonState;
    // A small delay to debounce the button (optional, depending on your button)
    delay(50);
  }
}

// Function to update the LEDs based on the current ledState
void updateLeds() {
  for (int i = 0; i < numLeds; i++) {
    digitalWrite(ledPins[i], (ledState & (1 << i)) ? HIGH : LOW); // Check each bit of ledState and set corresponding LED
  }
}