void setup() {
 pinMode(2,OUTPUT);
 pinMode(3,OUTPUT);
 pinMode(4, OUTPUT);
 pinMode(5, OUTPUT);
}


void loop() {  
digitalWrite(2, HIGH);
digitalWrite(2, LOW);
digitalWrite(3, LOW);
digitalWrite(4, LOW);
digitalWrite(5, LOW);
delay(500);
digitalWrite(2, LOW);
digitalWrite(3, HIGH);
digitalWrite(3, LOW);
digitalWrite(4, LOW);
digitalWrite(5, LOW);
delay(500);
digitalWrite(2, LOW);
digitalWrite(3, LOW);
digitalWrite(4, HIGH);
digitalWrite(4, LOW);
digitalWrite(5, LOW);
delay(500);
digitalWrite(2, LOW);
digitalWrite(3, LOW);
digitalWrite(4, LOW);
digitalWrite(5, HIGH);
digitalWrite(5, LOW);
delay(500);
}