void setup()
 {
  pinMode(13,OUTPUT);
  pinMode(12,OUTPUT);
  pinMode(11,OUTPUT);
 }
 void loop()
 {
  digitalWrite(13,1);
  digitalWrite(12,0);
  digitalWrite(11,0);
  delay(1000);
  digitalWrite(13,0);
  digitalWrite(12,1);
  digitalWrite(11,0);
  delay(1000);
  digitalWrite(13,0);
  digitalWrite(12,0);
  digitalWrite(11,1);
  delay(1000);
 }