int aG = 1;
int aY = 2;
int aR = 3;

int bG = 11;
int bY = 12;
int bR = 13;

void setup() {
pinMode(aG, OUTPUT);
pinMode(aY, OUTPUT);
pinMode(aR, OUTPUT);

pinMode(bG, OUTPUT);
pinMode(bY, OUTPUT);
pinMode(bR, OUTPUT);
}

void loop() {
digitalWrite(aR, LOW);

digitalWrite(bR, HIGH);

digitalWrite(aG, HIGH);
delay (3000);
digitalWrite(aG, LOW);

digitalWrite(aY, HIGH);
delay (3000);
digitalWrite(aY, LOW);

digitalWrite(aR, HIGH);
//
digitalWrite(bR, LOW);

digitalWrite(bG, HIGH);
delay (3000);
digitalWrite(bG, LOW);

digitalWrite(bY, HIGH);
delay (3000);
digitalWrite(bY, LOW);

digitalWrite(bR, HIGH);

}