/**
 * Functions. 
 * 
 * The trafficLight() turns ON the specified light and waits 2 seconds. 
 * Each call to trafficLight() specifies the pin in which a color LED
 * is connected, turns OFF all colors and then turn ON the one specified
 */
int RED = 0;
int YELLOW = 1;
int GREEN = 2;

void setup() 
{
  pinMode(RED, OUTPUT);
  pinMode(YELLOW, OUTPUT);
  pinMode(GREEN, OUTPUT);
}

void loop() 
{
  trafficLight(RED);
  trafficLight(YELLOW);
  trafficLight(GREEN);
}
  
void trafficLight(int color) 
{
  digitalWrite(RED, LOW);
  digitalWrite(YELLOW, LOW);
  digitalWrite(GREEN, LOW);
  digitalWrite(color, HIGH);
  delay(2000);
}
