“These letters, which are not exactly letters, but rather objects of art, will evidently cause trouble to the postal service of every country they pass through. What could these weirdly illustrated envelopes mean? — for these envelopes are themselves already part of the correspondence, sometimes even the most important part. This would be indecipherable to some pudding-headed postmaster from the back of beyond, or anywhere for that matter. Because, as examples of artistic labour, these fragments of correspondence will instantly embody the impropriety that art represents; as art is permanent rebellion in the history of the human race.“
— Bora Ćosić