void setup() 
{
  pinMode(2,OUTPUT);
  /*pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);*/
}

void loop() 
{
  digitalWrite(2, HIGH);
  /*digitalWrite(3, HIGH);
  digitalWrite(4, HIGH);
  digitalWrite(5, HIGH);
  digitalWrite(6, HIGH);
  digitalWrite(7, HIGH);*/
  delay(500);

  digitalWrite(2, LOW);
  /*digitalWrite(3, LOW);
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);
  digitalWrite(6, LOW);
  digitalWrite(7, LOW);*/
  delay(500);
}