#define l1 13
#define l2 8
#define l3 7
void setup() {
pinMode(l1, OUTPUT);
pinMode(l2, OUTPUT);
pinMode(l3, OUTPUT);
Serial.begin(9600);
}

void loop() {
 digitalWrite(l1, HIGH);
digitalWrite(l2, LOW);
digitalWrite(l3, LOW);
Serial.println("l1 on");
delay(6000);
digitalWrite(l1, LOW);
digitalWrite(l2, HIGH);
digitalWrite(l3, LOW);
Serial.println("l2 on");
delay(6000);
digitalWrite(l1, LOW);
digitalWrite(l2, LOW);
digitalWrite(l3, HIGH);
Serial.println("l3 on");
delay(6000);

}