RHYTHM 10, 1977, Belgrad. 'We are kneeling face to face, pressing our mouths together. Our noses are blocked with cigarette filters! Ulay says: 'I am breathing in oxygen. I am breathing out carbon dioxide.’ Abramovic: 'I am breathing in carbon dioxide. I am breathing out carbon dioxide.’ .The intimacy suggested by the video still is actually misleading. For almost twenty minutes, Ulay and Abramovic depend desperately on each other to stay alive. The physical struggle that ensues due to the lack of oxygen and to the breathing in of carbon dioxide is visibly exhausting. Ulay manages to control the rhythm of his breathing for slightly longer, but soon he is suffering too. They let go of each other's mouths, gasping to regain their breath. Compared to the other performances based on bodily stamina, this highly strenuous performance is relatively short, due to the lack of the most essential ingredient of life.