void setup() {
  // put your setup code here, to run o
  pinMode(2, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
 // this speeds up the simulation
 digitalWrite(2, HIGH);
 digitalWrite(4, LOW);
 digitalWrite(5, LOW);
 delay(1000);
 digitalWrite(4, HIGH);
 digitalWrite(5, LOW);
 digitalWrite(2,LOW);
 delay(1000);
 digitalWrite(5, HIGH);
 digitalWrite(2, LOW);
 digitalWrite(4, LOW);
 delay(1000);
}