//const byte ledPins[] = {15, 2, 0, 4, 5, 18, 19, 21, 22 ,23};
const byte ledPins[] = {21, 19, 18, 5, 17, 16, 4, 0, 2, 15};
const byte pwmChannels[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
const int pwmDuties[] = {
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  1023, 512, 256, 128, 64, 32, 16, 8, 4, 2,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
int ledCount;
int delayTime = 100;

void setup() {
  ledCount = sizeof(ledPins);
  for (int i = 0; i < ledCount; i++) {
    ledcSetup(pwmChannels[i], 1000, 10);
    ledcAttachPin(ledPins[i], pwmChannels[i]);
  }
}

void loop() {
  for (int i = 0; i < 20; i++) {
    for (int j = 0; j < ledCount; j++) {
      ledcWrite(pwmChannels[j], pwmDuties[i + j]);
    }
    delay(delayTime);
  }
  
  for (int i = 0; i < 20; i++) {
    for (int j = ledCount - 1; j >= 0; j--) {
      ledcWrite(pwmChannels[j], pwmDuties[i + (ledCount - 1 - j)]);
    }
    delay(delayTime);
  }
}