NZDF is a term which was first coined here in these very forums by, ahem, yours truly
it stands for Non-Zero Deviosity Factor, and refers to the practice of responding to certain requests for homework assistance with an answer that is devious to some extent
obviously, a student struggling with a homework problem, who makes a game attempt, and shows his work, and discusses what he's tried and what concepts he's having trouble with, is going to receive answers largely devoid of any deviosity
the idea is that the larger the deviosity, the more likely it is that the student will get into trouble if he hands in the answer he obtained here
and it's particularly effective if the answer actually happens to work correctly, but in a way so devious that the student doesn't twig onto the ruse but the teacher surely will
I wonder whether we should have a monthly award for the best response. The only danger with NZDF is that some future associate might look for your name on the web and come up with the code and just think WTF?