"Rough Shape," a dour yet cheeky exhibit at Samson by the sculptor duo Antoniadis & Stone, startles right out of the box with sheer dreariness on a grand scale. On first impression, the work is all big and breaking down: toppling towers of concrete, overturned staircases, and rusted steel.The works reference institutional architecture -- the kind found in places where the design is based on utility, not on aesthetics, or where the aesthetics are overtly modernist (such as the brutalist architecture of Boston City Hall). We can extend the metaphor and read a critique of crumbling institutions of power.