void setup() {
  // put your setup code here, to run once:
pinMode(7, OUTPUT);
pinMode(6, OUTPUT);
pinMode(5, OUTPUT);
pinMode(4, OUTPUT);
pinMode(3, OUTPUT);}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(7,HIGH);
delay(500);
digitalWrite(7,LOW);
delay(500);
digitalWrite(6, HIGH);
delay(500);
digitalWrite(6,LOW);
delay(500);
digitalWrite(5,HIGH);
delay(500);
digitalWrite(5,LOW);
delay(500);
digitalWrite(4, HIGH);
delay(500);
digitalWrite(4, LOW);
delay(500);
digitalWrite(3, HIGH);
delay(500);
digitalWrite(3, LOW);
delay(500);
}