#define red 2
#define yellow 6
#define green 11

void setup() {
   pinMode(red, OUTPUT);
   pinMode(yellow, OUTPUT);
   pinMode(green, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(red, HIGH);
  
  delay(2000); // this speeds up the simulation

  digitalWrite(red, LOW);
  digitalWrite(yellow, HIGH);
  delay(500);

  digitalWrite(red, LOW);
  digitalWrite(yellow, LOW);
  digitalWrite(green, HIGH);
  delay(2000);

  digitalWrite(green,LOW);
  digitalWrite(yellow, HIGH);
  delay(500);
  digitalWrite(yellow, LOW);

}