void setup(){
  
  pinMode(5,OUTPUT);
  pinMode(6,OUTPUT);
  pinMode(7,OUTPUT);

  }

 void loop(){
//3 second delay
  digitalWrite(5,HIGH);
  delay(3000);
  digitalWrite(5,LOW);
  digitalWrite(6,HIGH);
  delay(3000);
  digitalWrite(6,LOW);
  digitalWrite(7,HIGH);
  delay(3000);
  digitalWrite(7,LOW);

 
 }