16 miles of string.
"String was among the cheapest materials available, and Duchamp bought 16 miles of it, of which only about one mile was used, to prepare an entanglement in which the visitor experienced difficulties in finding his way to the paintings, a metaphor for the difficulties which the layman often encounters in the attempt to understand modern painting....During installation the string caught fire through spontaneous combustion and had to be replaced by another mile of string. "Imagine that these strings were really guncotton--they always are when they're attached to a light bulb, and I don't know how, but at a given moment they burned. Since guncotton burns without a flame, it was rather terrifying. But it worked out all right. It was rather funny." That left fourteen miles unused. "I gave it away," Duchamp recalls. "It made someone very happy--a kind of insurance, string enough to last him the rest of his life."
interesting new art blog..... 16 miles.. here.