// 4 WAY TRAFFIC LIGHT CONTROL

int r1 = 2;  int y1 = 3;  int g1 = 4;
int r2 = 5;  int y2 = 6;  int g2 = 7;
int r3 = 8;  int y3 = 9;  int g3 = 10;
int r4 = 11;  int y4 = 12;  int g4 = 13;

void setup(){
    pinMode(r1, OUTPUT); pinMode(y1, OUTPUT); pinMode(g1, OUTPUT);
    pinMode(r2, OUTPUT); pinMode(y2, OUTPUT); pinMode(g2, OUTPUT);
    pinMode(r3, OUTPUT); pinMode(y3, OUTPUT); pinMode(g3, OUTPUT);
    pinMode(r4, OUTPUT); pinMode(y4, OUTPUT); pinMode(g4, OUTPUT);
}

void loop(){

   digitalWrite(r2, HIGH); digitalWrite(r3, HIGH); digitalWrite(r4, HIGH);

  // Traffic light 1 
    digitalWrite(r1, HIGH); delay(7000); digitalWrite(r1, LOW); 
    digitalWrite(g1, HIGH); delay(7000); digitalWrite(g1, LOW); 
    digitalWrite(y1, HIGH); delay(5000); digitalWrite(y1, LOW); 
    digitalWrite(r1, HIGH); digitalWrite(r2, LOW);

  // Traffic light 2  
    digitalWrite(g2, HIGH); delay(7000); digitalWrite(g2, LOW); 
    digitalWrite(y2, HIGH); delay(7000); digitalWrite(y2, LOW); 
    digitalWrite(r2, HIGH); digitalWrite(r3, LOW);

  // Traffic light 3  
    digitalWrite(g3, HIGH); delay(7000); digitalWrite(g3, LOW); 
    digitalWrite(y3, HIGH); delay(7000); digitalWrite(y3, LOW); 
    digitalWrite(r3, HIGH); digitalWrite(r4, LOW);

  // Traffic light 4  
    digitalWrite(g4, HIGH); delay(7000); digitalWrite(g4, LOW); 
    digitalWrite(y4, HIGH); delay(7000); digitalWrite(y4, LOW); 
    digitalWrite(r4, HIGH);   
}