void setup()
{
  pinMode(13,OUTPUT);
  pinMode(11,OUTPUT);
  pinMode(10,OUTPUT);
}
void loop()
{
   digitalWrite(13, HIGH); 
   delay(1000); 
   digitalWrite(13, LOW);
   digitalWrite(11, HIGH);    
   delay(1000); 
   digitalWrite(11, LOW);
   digitalWrite(10, HIGH);    
   delay(1000); 
   digitalWrite(10, LOW);
}