const int ledPin = 13;

void setup() {
  Serial.begin(9600); 
  pinMode(ledPin, OUTPUT);
  Serial.println("type 1 / 0 / B / M");
}
void loop()
{
  if (Serial.available() > 0) 
  {
    char data = Serial.read();
    if (data == '1') 
    {
      digitalWrite(ledPin, HIGH);
    }
    else if (data == '0') 
    {
      digitalWrite(ledPin, LOW);
    }
    else if (data == 'B')
    {
      while (data == 'B')
      {
        digitalWrite(ledPin, HIGH);
        delay(500);
        digitalWrite(ledPin, LOW);
        delay(500);
        if (Serial.available() > 1)
        {
          char data = Serial.read();
          break;
        }
      }
      Serial.print("\n");
    }
    else if (data == 'M') 
    {
      Serial.println("I learned how to use serial communication between the computer and Arduino.");
      Serial.print("\n");
    }
  }
}