void setup() {
  // put your setup code here, to run once:
  pinMode(0, OUTPUT);
  pinMode(1, OUTPUT);
  pinMode(2, OUTPUT);
  pinMode(4, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  // ? Make LED ON
  digitalWrite(0, HIGH);
  delay(100);
    digitalWrite(1, HIGH);
  delay(100);
    digitalWrite(2, HIGH);
  delay(100);
    digitalWrite(4, HIGH);
  delay(100);

// ? Make LED OFF
digitalWrite(0,LOW);
delay(100);

digitalWrite(1,LOW);
delay(100);
digitalWrite(2,LOW);
delay(100);

digitalWrite(4,LOW);
delay(100);
}