I found them beside of stairs of floor 1th on Nicoles Hall. Actually I have seen them in other place in campus. Those seem to just large stature boxs, made of iron and plastic. Those are taller than a man of ordinary stature. What they are always together located like twins is a distinctive. While I am ovserving the boxs, so many people come to use them. It seems very popular to our campus students and professors. Its appearance is not gorgeous, even just looks like big tin! However, everytime, everday there are lots peple in front of the boxs. Even sometimes they get into line for using them with some coins or paper money!  What are these ?