int l1=13;
int l2=12;
int l3=11;
int l4=10;

void setup() {
  // put your setup code here, to run once:
 Serial.begin(9600);
 pinMode(l1, OUTPUT);
 pinMode(l2, OUTPUT);
 pinMode(l3, OUTPUT);
 pinMode(l4, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(l1, HIGH);
delay(1000);
digitalWrite(l1, LOW);
digitalWrite(l2, HIGH);
delay(1000);
digitalWrite(l2, LOW);
digitalWrite(l3, HIGH);
delay(1000);
digitalWrite(l3, LOW);
digitalWrite(l4, HIGH);
delay(1000);
digitalWrite(l4, LOW);

delay(500);
digitalWrite(l1, HIGH);
digitalWrite(l2, HIGH);
digitalWrite(l3, HIGH);
digitalWrite(l4, HIGH);

delay(1000);
digitalWrite(l1, LOW);
digitalWrite(l2, LOW);
digitalWrite(l3, LOW);
digitalWrite(l4, LOW);
delay(1000);
}