void setup() {
  pinMode(10, OUTPUT) ;
  digitalWrite(10, LOW);
  pinMode(8, OUTPUT);
  digitalWrite(8, LOW);
  pinMode(7,OUTPUT);
  digitalWrite(7, LOW);
  pinMode(13, OUTPUT);
  digitalWrite(13, LOW);

}

void loop() {
  digitalWrite(10, HIGH);
  delay(100);
  digitalWrite(10, LOW);
  delay(100);
  digitalWrite(8, HIGH);
  delay(100);
  digitalWrite(8, LOW);
  delay(100);
  digitalWrite(7, HIGH);
  delay(100);
  digitalWrite(7, LOW);
  delay(100);
  digitalWrite(13, HIGH);
  delay(100);
  digitalWrite(13, LOW);
  delay(100);

}