void randomLED(){
  float rNum = random(100);
  if (rNum < 25){
    arduino.digitalWrite(left, Arduino.HIGH);
    arduino.digitalWrite(right, Arduino.LOW);
    arduino.digitalWrite(up, Arduino.LOW);
    arduino.digitalWrite(down, Arduino.LOW);
  }
  
  if (rNum >= 25 && rNum <50){
    arduino.digitalWrite(left, Arduino.LOW);
    arduino.digitalWrite(right, Arduino.HIGH);
    arduino.digitalWrite(up, Arduino.LOW);
    arduino.digitalWrite(down, Arduino.LOW);
  }
  
  if (rNum >= 50 && rNum <75){
    arduino.digitalWrite(left, Arduino.LOW);
    arduino.digitalWrite(right, Arduino.LOW);
    arduino.digitalWrite(up, Arduino.HIGH);
    arduino.digitalWrite(down, Arduino.LOW);
  } 
  
  if (rNum >= 75 && rNum <100){
    arduino.digitalWrite(left, Arduino.LOW);
    arduino.digitalWrite(right, Arduino.LOW);
    arduino.digitalWrite(up, Arduino.LOW);
    arduino.digitalWrite(down, Arduino.HIGH);
  }
}