Re: == 2024 Bitcoin halving tribute puzzle - Challenge to win 10,000,000 sats! ==
The good news is that you are on the right track, the better news is that the rule is indeed simple.
I hope you don't mess with me, and that I'm indeed on the right track. 
If you encode the word's sequential number with the word, then each word and its sequential number form a "block" that can be placed out of order, which is a very important way to write seed phrases in secret.
That's a good point. For example, the word "brisk" comes with position "2". But, what do you mean with "can be placed out of order"? I understand it as "if we have a word and its position, then the order is irrelevant to us". For example, LwE~T1 could be the word "property" along with the position "10". I say the rule is simple because it uses one or two "blocks" of information about how to choose the cards
OK, so there's more than just word and position. I can think of a third piece of information.(even the black ones need to be chosen because I may have several different sets of cards for myself, for different purposes, and sometimes they tend to get mixed up with each other)
But, we only have one black card with two sides. Not entirely sure why you would want sets of such cards. A little bit off-topic, but do you feel confident that having your seed phrase in ciphertext is a wise choice? I think it's extremely unlikely that someone can steal your coins, but with a slight loss of memory, you might get locked out of your funds.