const int LED1 = 2;
const int LED2 = 3;
const int LED3 = 4;
const int LED4 = 5;


void setup() {
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(LED3, OUTPUT);
  pinMode(LED4, OUTPUT);

}

void loop() {
  digitalWrite(LED1, HIGH);
  delay(1000);
  digitalWrite(LED2, HIGH);
  delay(1000);
  digitalWrite(LED3, HIGH);
  delay(1000);
  digitalWrite(LED4, HIGH);
  delay(1000);
  digitalWrite(LED4, LOW);
  delay(1000);
  digitalWrite(LED3, LOW);
  delay(1000);
  digitalWrite(LED2, LOW);
  delay(1000);
  digitalWrite(LED1, LOW);
  delay(1000);

}