Cone ( Gordon Matta_Clark )

Conical Intersect :

Matta-Clark’s contribution to the Paris Biennale of 1975, manifested his critique of urban gentrification in the form of a radical incision through two adjacent 17th-century buildings designated for demolition near the much-contested Centre Georges Pompidou, which was then under construction. For this antimonument, or “nonument,” which contemplated the poetics of the civic ruin, Matta-Clark bored a tornado-shaped hole that spiraled back at a 45-degree angle to exit through the roof. Periscopelike, the void offered passersby a view of the buildings’ internal skeletons. 

and :

http://images.google.fr/images?q=gordon+matta-clark+conical+intersect&hl=fr

http://www.postmedia.net/02/mattaclark.htm

http://www.guggenheim.org/exhibitions/past_exhibitions/postmedia/mattaclark.html

http://www.multimedia.au.dk/~nrune/lav/web/opg3ref/matta_clark/

http://www.multimedia.au.dk/~nrune/lav/program.htm