Arduino Snap Circuit siren controller

#define R1 6
#define R2 7
#define R3 9
#define R4 8


void setup() {
 pinMode(R1, OUTPUT);
 pinMode(R2, OUTPUT);
 pinMode(R3, OUTPUT);
 pinMode(R4, OUTPUT);

digitalWrite(R1,HIGH);
digitalWrite(R2,HIGH);
digitalWrite(R3,HIGH);
digitalWrite(R4,HIGH);


}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(R1, LOW);
delay(3000);
digitalWrite(R1, HIGH);

digitalWrite(R2, LOW);
delay(3000);
digitalWrite(R2, HIGH);

digitalWrite(R3, LOW);
delay(3000);
digitalWrite(R3, HIGH);

delay(4000);

digitalWrite(R2, LOW);
digitalWrite(R1, LOW);
delay(3000);
digitalWrite(R1, HIGH);
digitalWrite(R2, HIGH);

digitalWrite(R2, LOW);
digitalWrite(R3, LOW);
delay(3000);
digitalWrite(R2, HIGH);
digitalWrite(R3, HIGH);

digitalWrite(R1, LOW);
digitalWrite(R3, LOW);
delay(3000);
digitalWrite(R3, HIGH);
digitalWrite(R1, HIGH);


digitalWrite(R1, LOW);
digitalWrite(R2, LOW);
digitalWrite(R3, LOW);
delay(3000);
digitalWrite(R3, HIGH);
digitalWrite(R2, LOW );
digitalWrite(R1, HIGH);

digitalWrite(R3, LOW);
digitalWrite(R1, LOW);
delay(3000);
digitalWrite(R1, HIGH);
digitalWrite(R3, HIGH);

delay(3000);     




}