Display LED - Incremental

void setup() {
  // put your setup code here, to run once:
  int i = 0;
  for (int i = 0; i <= 2; i++) {
    pinMode(i, OUTPUT);
  }
}

void loop() {
  int i = 0;

  // put your main code here, to run repeatedly:
  for (int i = 0; i <= 2; i++) {
    digitalWrite(i, HIGH);
    delay(250);
  }
  for (int i = 0; i <= 2; i++) {
    digitalWrite(i, LOW);
    delay(250);
  }
}