Another of Applegate's training innovations was the use of particularly intense combat firing ranges, which he called the "house of horrors". A cross between an obstacle course, a haunted house, and a shooting range, it used a three dimensional layout with stairs and tunnels, pop-up targets, deliberately poor lighting, psychologically disturbing sounds, simulated cobwebs and bodies, and blank cartridges being fired towards the shooter. The range was designed to have the greatest possible psychological impact on the shooter, to simulate the stress of combat as much as possible, and no targets were presented at distances of greater than from the shooter.