void setup() {
  pinMode(10, OUTPUT);
  pinMode(11, OUTPUT);
  pinMode(12, OUTPUT);
  pinMode(6, INPUT_PULLUP);
  pinMode(7, INPUT_PULLUP);
}

void loop() {
  bool sw6 = digitalRead(6);
  bool sw7 = digitalRead(7);
  if (sw6 == 0 && sw7 == 0) {
    digitalWrite(10, HIGH);
    delay(500);
    digitalWrite(10, LOW);
    digitalWrite(11, HIGH);
    delay(500);
    digitalWrite(11, LOW);
    digitalWrite(12, HIGH);
    delay(500);
    digitalWrite(12, LOW);
  }
  else if (sw6 == 0 || sw7 == 0) {
   digitalWrite(12, HIGH);
    delay(500);
    digitalWrite(12, LOW);
    digitalWrite(11, HIGH);
    delay(500);
    digitalWrite(11, LOW);
    digitalWrite(10, HIGH);
    delay(500);
    digitalWrite(10, LOW);
  }
  else {
    digitalWrite(10, LOW);
    digitalWrite(11, LOW);
    digitalWrite(12, LOW);
  }
}