The annex to this chapter gives examples of circumstances where an invention may be regarded as obvious or where it may involve an inventive step. It is to be stressed that these examples are only for illustrative purposes and that the applicable principle in each case is "was it obvious to a person skilled in the art?" (see IV, 9.8). Examiners should avoid attempts to fit a particular case into one of these examples if it is not clearly applicable. Also, the list is not exhaustive.