My high school engineering team built this devise during my senior year (1994-5). It was for the National Engineering Design Challenge (NEDC). That year the NEDC problem was to be able to allow a person paralyzed from the neck down and knees up to give a presentation using an overhead projection, and transparencies. The devise had to do the specific following tasks. Remove a hanging file folder from a file cabinet drawer, place the folder on a table, open the folder, display the five transparencies in the folder on an overhead projector, put the five transparencies back in the folder in order, pickup the folder.