void setup() {
  // put your setup code here, to run once:
for (int i = 0; i<5; i++)
pinMode (i, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
for (int i= 0; i<5 ; i++)
digitalWrite ( i,HIGH);
delay(1000);

for (int i = 0; i< 5 ; i++)

digitalWrite ( i,LOW);
delay(1000);
}