I visited the Venice Biennial a couple of weeks ago. This piece by Michelangelo Pistoletto (great name!) was one of the first I saw there, and I was instantly impressed by the simplicity and effectiveness of it. Pistoletto uses the mirror, which is a traditional object and recurring theme in the history of art. The mirrors are brutally vandalised, with large holes and cracks in them, and splinters lying all around. Although presented in a quiet way, you could still feel the action.

Michelangelo Pistoletto, 'Twenty-two Less Two', 2009. Mirrors, wood, 22 pieces.