t the University of Utah in Salt Lake City, computer scientist John M. Hollerbach puts a lab staff member on the SARCOS Treadport, a device that mimics the tug and pull of acceleration. Walking on a treadmill, the staffer is surrounded by a projected simulation of a Western mountainside. On a real hill, hikers must struggle with their own inertia to surmount the slope, a sensation no ordinary treadmill can provide. The Treadport uses force-feedback to push or pull at the user, uncannily evoking the sensation of climbing, a new dimension of realism for this type of simulation. From the book Robo sapiens: Evolution of a New Species, page 137 top.