void setup() {
  // put your setup code here, to run once:
pinMode(8, OUTPUT);
pinMode(10, OUTPUT);
pinMode(12, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(8, HIGH);
delay(400);
digitalWrite(8, LOW);
Serial.print("S");
delay(400);
digitalWrite(10, HIGH);
delay(900);
digitalWrite(10, LOW);
Serial.print("O");
delay(900);
digitalWrite(12, HIGH);
delay(400);
digitalWrite(12, LOW);
Serial.print("S");
delay(400);
}