I explored "watering up the curriculum" and was distressed taht the "feature example" of a "big idea" exploration stated unequivocally that there were only two kinds of lines, parallel and perpendicular.
I got a reply to my email about it (a very short one since I figured odds were good it would get lost in the ether). So that it could be corrected, what were other kinds of lines? I"m afraid it does make me wail and gnash my teeth a bit. A person attempting to pretend to approach the faintest pretense of scholarship would have looked it up instead of trying to get the answer by emailing back to an unknown person, though I *suppose* that a scholar might have asked the question and also looked it up, or at least planned to confirm what the unknown person said. And yes, it also rubbed that raw nerve that's sensitive to so many educators' disdain for actually *understanding* math. It's just something you have to make a card for, get some 'big idea' to recite, and endure.
(That's right, I"m one of those complete weirdos who finds the harmony and balance in mathematics invigorating and delightful - and I'm not talking advanced stuff.)
I suggested that instead of saying there were *only* two kinds of lines, that it should say there were two important relationships between lines (and that indeed, perpendicular and parallel didn't describe the individual line but the relationship between two lines -knowing that the fellow probably considered that unnecessary knowledge).