int redLED = 2;
int yelLED = 3;
int greLED = 4;

void setup() {
  // put your setup code here, to run once:
  pinMode (redLED, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  //Alternate();
  KnightRider();
  //Traffic();
}
void Alternate() {
  digitalWrite(redLED, HIGH);
  digitalWrite(yelLED, LOW);
  delay(500);
  digitalWrite(redLED, LOW);
  digitalWrite(yelLED, HIGH);
  delay(500);
}

void KnightRider() {
  digitalWrite(redLED, HIGH);
  digitalWrite(yelLED, LOW);
  delay(500);
  digitalWrite(redLED, LOW);
  digitalWrite(yelLED, HIGH);
  delay(500);
  digitalWrite(yelLED, LOW);
  digitalWrite(greLED, HIGH);
  delay(500);
  digitalWrite(greLED, LOW);
  digitalWrite(yelLED, HIGH);
  delay(500);
}

void Traffic() {
  digitalWrite(greLED, LOW);
  digitalWrite(redLED, HIGH);
  digitalWrite(yelLED, LOW);
  delay(1000);
  digitalWrite(yelLED, HIGH);
  delay(1000);
  digitalWrite(redLED, LOW);
  digitalWrite(yelLED, LOW);
  digitalWrite(greLED, HIGH);
  delay(1000);
}