const int numLEDs = 16;          // Number of LEDs
const int ledPins[numLEDs] = {2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17};  // LED pins

void setup() {
  // Set all LED pins as output
  for (int i = 0; i < numLEDs; i++) {
    pinMode(ledPins[i], OUTPUT);
  }
}

void loop() {
  // Turn on each LED in sequence
  for (int i = 0; i < numLEDs; i++) {
    digitalWrite(ledPins[i], HIGH);  // Turn on LED
    delay(10);                      // Wait for 100 milliseconds
    digitalWrite(ledPins[i], LOW);   // Turn off LED
  }
}