What Makes a parody American Gothic?

My latest addition is a copy of April 2014 issue of Quilt Life Magazine. There is an article including 8 photos from an America n Gothic Quilting Challenge. Each of the 8 quilts parodies Grant Wood's masterpiece to greater or lesser degree.
For example, One shows the couple and the farmhouse rather faithfully except that both are in outfits with bold patterns and the woman has a sly smirk as if to day 'I can't believe I got him to wear that!'
At the other end of the spectrum is a parody showing Doctor Who and Rose with the Tardis as a backdrop and a Sonic Screwdriver instead of a pitchfork. If you are not a Who fan (They call themselves Whovians), you may not understand most of what I just said, but the point of it is, the is no Gothic style window in the background, and no pitchfork. I am a Who fan, but would not add this to my American Gothic collection because to me it has to have At least one of those two elements, or the actual original couple, to count as a true A.G. parody.

Similarly the recent US magazine special issue on the movie 'Divergent' caught my eye (see below) but I did not buy a copy  for the same reasons I just stated. Just a stern faced couple is NOT enough!
If you look through my collection on this site, you'll find others I consider borderline and maybe one or two that really don't belong at all. What do you think? What is the minimum set of elements that make a valid A.G. parody? DO you have any example of 'minimalist' parodies? Let me know and we can share them with other fans.