Andy was able to secure the poster from inside the tunnel because it was only taped at the top corners, allowing it to function as a simple, gravity-weighted flap. When Warden Norton inspects the cell the morning after the escape, he angrily rips the poster of Raquel Welch off the wall, revealing the tape configuration. Andy did not need to tape the bottom or sides of the poster to keep it flat; the weight of the heavy paper naturally kept it flush against the concrete wall. When Andy entered the hole, he simply lifted the bottom of the poster, crawled through the opening headfirst, and let the paper fall back into place behind him. The film prepares us for this physical reality during the earlier scene where Norton first inspects Andy's cell and adjusts the poster, demonstrating how it hangs freely. By utilizing the natural drape of the paper, Andy ensured his tunnel remained completely hidden from the daily cell checks without needing an accomplice to seal it from the outside. This simple mechanical trick perfectly mirrors Andy's entire approach to his imprisonment: utilizing the natural, overlooked properties of his environment to quietly outsmart his captors.■