void setup() {
  // put your setup code here, to run once:
  pinMode(2, INPUT_PULLUP);
  pinMode(4, INPUT_PULLUP);
  pinMode(7, INPUT_PULLUP);
  pinMode(8, INPUT_PULLUP);
  Serial.begin(9600);
}

String presetMsg1 = "Ora ora ora ora ora ora ora";
String presetMsg2 = "Muda muda muda muda muda muda";
String presetMsg3 = "Omae wa mo shinderu";
String presetMsg4 = "Nani!!";

int prevStates[] = {HIGH,HIGH,HIGH,HIGH};

void loop() {
  // put your main code here, to run repeatedly:
  int b1 = digitalRead(2);
  int b2 = digitalRead(4);
  int b3 = digitalRead(7);
  int b4 = digitalRead(8);

  if (b1 == LOW && prevStates[0]==HIGH){
    Serial.println(presetMsg1);
  }
  else if (b2 == LOW && prevStates[1]==HIGH){
    Serial.println(presetMsg2);
  }
  else if (b3 == LOW && prevStates[2]==HIGH){
    Serial.println(presetMsg3);
  }
  else if (b4 == LOW && prevStates[3]==HIGH){
    Serial.println(presetMsg4);
  }

  prevStates[0] = b1;
  prevStates[1] = b2;
  prevStates[2] = b3;
  prevStates[3] = b4;


  delay(20);
}