int ledPins[] = {0, 3, 5, 6, 9, 10, 11};
int carPins[] = {1, 2, 4, 7, 8, 12, 13};
int numLeds = 7;
int numCars = 7;
int delayTime = 100; // Initial delay time in milliseconds
int carCount = 0;
//int direction = 1;  // 1 for forward, -1 for reverse
int currentLed = 0;  // Current LED index
int intensity = 0;  // PWM intensity (0 to 255)

void setup() {
  // Set PWM pins as OUTPUT
  for (int i = 0; i < numCars; i++) {
    pinMode(ledPins[i], OUTPUT);
    pinMode(carPins[i], OUTPUT);
  }
}

void loop() {
  // Turn off all LEDs
  for (int i = 0; i < numLeds; i++) {
    analogWrite(ledPins[i], 0);
    analogWrite(carPins[i], 0);
  }

  // Set the intensity of the current LED
  analogWrite(carPins[carCount], intensity);

  if (carCount % 2 == 0) {
    analogWrite(ledPins[currentLed], intensity);
    currentLed += 1;
    if (currentLed == numLeds) {
      currentLed = 0;
    }
  }

  carCount += 1;
  if (carCount == numCars) {
    carCount = 0;
  }

  /** Reverse direction when reaching the end LEDs
  if (currentLed == numLeds || currentLed == -1) {
    direction = -direction;
    currentLed += 2 * direction;
  }
  **/

  // Adjust the intensity
  intensity += 1 * 10; // Change intensity by 10 each step
  if (intensity < 0) {
    intensity = 0;
  }
  if (intensity > 255) {
    intensity = 255;
  }

  // Delay to control the rhythm
  delay(delayTime);

  // Change the delay time for variation
  delayTime = map(analogRead(A0), 0, 1023, 50, 300); // Adjust rhythm with a potentiometer on A0
}