If it has an L2 somewhere on the front or back of the card, I would say it is a card. It doesn't matter if it is the reverse of another card or a different MCD of the same sentence.
If you've done the card at least once, and it isn't due on Dec 31, 2017, or 20 full months after you start, you have met the challenge.
If I'm 1000 cards short on Dec 31 next year, and I review each of those cards that day, so that they are due Jan 1, I've met the challenge.
I'd like to keep it open and simple. People are free to hold themselves to higher standards.
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