int led1 = 13;
int led2 = 11;
int led3 = 9;

void setup() {
 pinMode(led1,OUTPUT);
 pinMode(led2,OUTPUT);
 pinMode(led3,OUTPUT);
}

void loop() {
 digitalWrite(led1,1);
 digitalWrite(led2,1);
 digitalWrite(led3,1);
delay(1000);

 digitalWrite(led1,0);
 digitalWrite(led2,0);
 digitalWrite(led3,0);
delay(1000);

}