int l1=11;
int l2=10;
int l3=9;
int l4=8;

void setup() {
pinMode(l1, OUTPUT);
pinMode(l2, OUTPUT);
pinMode(l3, OUTPUT);
pinMode(l4, OUTPUT);
}
void loop() {

digitalWrite(l1, HIGH);
delay(500);
digitalWrite(l1, LOW);
digitalWrite(l2, HIGH);
delay(500);
digitalWrite(l2, LOW);
digitalWrite(l3, HIGH);
delay(500);
digitalWrite(l3, LOW);
digitalWrite(l4, HIGH);
delay(500);
digitalWrite(l4, LOW);
delay(1000);
digitalWrite(l1, HIGH);
digitalWrite(l2, HIGH);
digitalWrite(l3, HIGH);
digitalWrite(l4, HIGH);
delay(500);
digitalWrite(l1, LOW);
digitalWrite(l2, LOW);
digitalWrite(l3, LOW);
digitalWrite(l4, LOW);
delay(500);

}