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The art billboard ostensibly reclaims space from the commercial commandeering of your senses, to return to some more mythically "creative" or "beautiful" use. This is the classic "poetic fissuring" of art. And Gonzalez-Torres's billboards were pinnacle art billboards, performing the usual art thing of reneging on the advertorial demand to shout something, and instead using the usual artistic silence as its loss, an empty bed, a space for your own private thoughts, the missing partner, communication, just you to project you own on white sheets.