Magnetic Chalk holder

Well... I though about how one of my teachers who uses a chalkboard still. I remembered when in her class she would have to use paper towel to hold the chalk, because she was allergic, and the dust gets on your hands, and it is a pain to get off. So i made a chalk holder that can have multiple sizes of chalks fit in it. But i thought of a problem about how to store it, so i made a small hole on the back to fit a magnet on it.