Potentiometer — LED wave

void loop() {
  int potValue = analogRead(POT_PIN);

  // Initialize all LED brightness levels to 0 (off)
  int b1 = 0, b2 = 0, b3 = 0, b4 = 0;

  // LED 1 Zone: 0 to 255
  if (potValue >= 0 && potValue < 256) {
    b1 = calculateBrightness(potValue);
  }
  // LED 2 Zone: 256 to 511
  else if (potValue >= 256 && potValue < 512) {
    b2 = calculateBrightness(potValue - 256);
  }
  // LED 3 Zone: 512 to 767
  else if (potValue >= 512 && potValue < 768) {
    b3 = calculateBrightness(potValue - 512);
  }
  // LED 4 Zone: 768 to 1023
  else if (potValue >= 768 && potValue <= 1023) {
    b4 = calculateBrightness(potValue - 768);
  }

  // Send the calculated fading brightness to the PWM pins
  analogWrite(LED_1, b1);
  analogWrite(LED_2, b2);
  analogWrite(LED_3, b3);
  analogWrite(LED_4, b4);

  delay(5); // Small delay for stable readings
}

// Helper function to turn a 0-255 position into a fade up/down brightness (0-255)
int calculateBrightness(int localValue) {
  if (localValue < 128) {
    // First half: Fade UP (0 to 127 steps map to 0 to 254 brightness)
    return localValue * 2;
  } else {
    // Second half: Fade DOWN (128 to 255 steps map back down to 0 brightness)
    return (255 - localValue) * 2;
  }
}