void setup() {
  // put your setup code here, to run once:
pinMode ( 7, OUTPUT);
pinMode ( 6, OUTPUT);
pinMode ( 5, OUTPUT);
pinMode ( 4, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
int nilai_delay = 200;
digitalWrite ( 7, HIGH ) ; 
delay (nilai_delay);
digitalWrite ( 6, HIGH ) ; 
delay (nilai_delay);
digitalWrite ( 5, HIGH ) ; 
delay (nilai_delay);
digitalWrite ( 4, HIGH ) ; 
delay (nilai_delay);

digitalWrite ( 7, LOW ) ; 
delay (nilai_delay);
digitalWrite ( 6, LOW ) ; 
delay (nilai_delay);
digitalWrite ( 5, LOW ) ; 
delay (nilai_delay);
digitalWrite ( 4, LOW ) ; 
delay (nilai_delay);

}