Bars of colored lights now trace the outlines and suggest the levels of the distinctive, sail-like façade of Pittsburgh’s August Wilson African American Cultural Center. The new work, titled “Give Light to the Whole Circumference,” is by Pittsburgh’s Rainbow Serpent Collective, and it’s more than eye candy for passersby on Liberty Avenue. The artists say the piece, which officially premieres with a celebration at the Center on Thursday night, was designed to communicate key themes from two plays by the building’s Pulitzer Prize-winning namesake.