Polly Apfelbaum’s great floor pieces at the ICA keep you looking down, but you’ll never look floorward at the Fabric Workshop and Museum ’s new wallpaper exhibit. From Warhol’s cows to Virgil Marti’s bullies, the wonders of repeat patterns pasted to the plaster will be yours. (Image is Marti’s black-light wallpaper installation at PAFA, summer 2001.) Tonight’s opening lecture at 6 pm. by former ICA curator, Judith Tannenbaum (now, Richard Brown Baker Curator of Contemporary Art at the RISDI Museum) will help elucidate why wallpaper in some hands is so darned subversive.