#include <Arduino.h>

const int ledPins[] = {
  2, 3, 4, 5, 6, 7, 8, 9, 10, 11
};

void setup() {
  for (int i = 0; i < 10; i++) {
    pinMode(ledPins[i], OUTPUT);
  }
}

void loop() {
  for (int i = 0; i < 10; i++) {
    analogWrite(ledPins[i], i * 255 / 10);
    delay(100);
  }
}