Arduino traffic lights

traffic_lights

int red = 13;
int yellow = 12;
int green = 11;

int ON=HIGH;
int OFF=LOW;

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

void loop(){
changeLights();
delay(100);
}
 
void changeLights(){
  
digitalWrite(yellow,OFF);
digitalWrite(red,OFF);
digitalWrite(green,ON);
delay(1000);

digitalWrite(yellow,ON);
digitalWrite(red,OFF);
digitalWrite(green,OFF);
delay(1000);
 
 
digitalWrite(yellow,OFF);
digitalWrite(red,ON);
digitalWrite(green,OFF);
delay(1000);
}