Ai Weiwei chose the clinic of Alcatraz as the setting for the site-specific installation Blossom. In this piece he filled the original porcelain fixtures, the bathtubs, sinks and toilets with masses of porcelain flowers. Looking like frothy bubbles from a distance, a closer inspection reveals this hopeful flowering.  It’s a stunning, subtle work, such a contrast between the dirty and sickly connotations of the clinic’s bathrooms and the flourishing purity of the flowers,  I find it profound that the same material, porcelain could convey both of these extremes.