How can a museum present the experience of public events, and the objects used in them, in an institutional context? (see: conceptual edifices) A noteworthy case is the life and afterlife of the objects used by Joanna Rajkowska during her Dotleniacz (Oxygenator) project. The object here is a device for ozonizing the air surrounding a man-made pond. It was both a concealed, technical element of the project – an ordinary machine – as well as its essence: It was the key mechanism for the entire process of oxygenation. The object constitutes a remainder, a relic of a project that existed in a specific public space for a limited period of time. Reduced to a mechanical device, itremains both a functional object (as opposed to a prototype or a symbol), and an artistic device (see: 1:1 scale), sustaining its aura as a part of a renowned art project (see: coefficient of art).