Near the end of Shakespeare’s “Macbeth,” the title character is warned that he will be defeated in his maniacal quest for power when “Birnam Wood comes to Dunsinane,” a geographical impossibility. But his clever enemies follow through on this threat by camouflaging themselves behind giant tree branches that, as the soldiers move forward, appear to be a forest on the move. Touring The Yard, Chicago Shakespeare Theater’s (CST) grandly innovative new venue on Navy Pier — where “The Toad Knew,” a work by the French spectacle-maker James Thierree, will officially inaugurate the space on Sept. 19 — you can only wonder what the Bard might have made of a theater that in many ways is designed to be its own movable “forest.” Andy Hayles of Charcoalblue demonstrates how The Yard at Chicago Shakespeare sits right under the tent at Navy Pier. | Max Herman/For the Sun-Times In an extraordinary example of architectural, engineering and theatrical re-purposing — devised by the Chicago-based firm of Adrian Smith + Gordon Gill Architecture and the UK-based theater consultancy firm, Charcoalblue, in consultation with CST’s executive director, Criss Henderson — The Yard marks the transformation of a single, large, underused outdoor venue (Navy Pier’s former Skyline Stage, renowned for its white tent-like “roof”) into an enclosed structure whose nine, 35,000-pound steel “towers” can be easily moved into 10 dramatically different configurations seating audiences of 400 to 800  people, and conforming to the scale and spirit of each production. Each of the towers is a self-contained ecosystem with heating and ventilating connectors, electrical connections, acoustical panels and a sprinkler system. And these towers, as well as the seats and stage, can be moved into place by a team of just three technicians thanks to the use of “air skids” inserted beneath each tower that can be pressurized to lift the structures 3/8 of an inch off the ground on a bed of compressed air. An interior view of Chicago Shakespeare Theater’s The Yard, its new, third performance space on Navy Pier, photographed on Sept. 13, 2017. | Max Herman/For the Sun-Times “The technology is much like that used in a