I have been dreaming to have a whiteboard that I can write out many colors as I like it to be. But, please pay attention! I don't want to waste a penny on ink that will frequently eat out my money, let alone that kind of untoleratable odd. So, I also hope that I have a magic pen that I can write with any color I want. It will show out when the pen contact at the board. It should be a electric board that has a sensor inside. This sensor is used to interact with magic pen. The magic...