After opening night of a three-performance run of the Lisp’s musical FUTURITY, we got on stage to take a look at the set design, specifically the “Steam Brain,” the artificial intelligence device Civil War soldier Julian Munro tries to create in the performance. The Brain, a percussion sculpture/assemblage art piece, was built by Lisps drummer Eric Farber out of objects from dumpster-diving missions, alley walks, and sessions of flea market haggling. Elements of the contraption with moving parts were made by Farber with help from Peter Doucette, Stephen Setterlun, and the staff of the American Repertory Theater scene shop. The show’s iconic backdrop, a rusted, painted sheet of metal, as well as other visual elements — including books and letters from the era — are the work of production designer Emily Orling. Here’s an up-close look at what you’ll see on stage during Friday and Saturday night’s performances of FUTURITY.