2016-10-23 Robert Smithson machine - Google 検索 https://www.google.com/search?q=Robert+Smithson+machine&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwi2u5H34fPPAhVD2LwKHch1DmcQsAQIHQ&biw=1436&bih=803#imgrc=_