The vast majority of people with mental retardation have IQ levels of 55 to 69 and are considered mildly retarded. Mildly retarded children often go undiagnosed until they are well into their school years. They are often slower to walk, talk, and feed themselves than most other children.
When Tom Six began creating the Human Centipede sequels, he envisioned a trilogy that works as a movie centipede. Each sequel opens with the ending of the previous film, as the events of that film influence said sequel.
The book was made into the film Sphere in 1998, directed by Barry Levinson, with a cast including Dustin Hoffman (Norman Johnson, renamed Norman Goodman), Samuel L. Jackson (Harry Adams), Peter Coyote (Harold Barnes), Liev Schreiber (Ted Fielding), and Sharon Stone (Beth Halpern, renamed Beth Halperin).