I meant the kitchen knife analogy as more of a general illustration that actual use of something is more important than straightforward interpretation of that object's purported purpose, rather than as a case of patentability :-) I fully agree that the use of kitchen knife as a murder weapon would be non-novel, given that sharp objects have been used to cause death since prehistoric times, as well as obvious, given that sharp objects are known to cause bodily harm, which is known to cause death.