You have four cards placed in a 2x2 grid pattern. Each card is randomly placed either face up or face down. Your goal is to flip all the cards face-up. But, there are a few restrictions:
- You are blindfolded and never know which cards are face up or face down. Nor do you know how many cards are flipped either way.
- Your movements for flipping cards are limited. Each turn you can flip either one or two cards.
- You will only be told when all cards are face up. You will get no other notification on how the cards are orientated.
What are the fewest amount of turns required to ensure all four cards are (eventually) flipped face up? And how?
Ascii art on how the layout may look. Each card represents a card:
1 2
3 4
Sidenote: When this brain teaser was first told to me last week, the person explained the possible limited card movements as, roughly, "you can either flip the diagonal cards, a column of cards, or a row of cards. Or, you can flip just a single card.". I'm pretty sure the way I explained it ("each turn, you can only flip one or two cards") is the same and much easier to understand, so I guess that lowers the puzzle difficulty a little bit for you, the reader.
Solution:
