The puzzle “Noughts and Crosses”
was published in a book intended to train the reader towards his application for Mensa membership.
Basically three upper rows of a 4x4 matrix were given (see below) and
the solver was requested to “fill the bottom line of the matrix with a combination of noughts and crosses that logically completes the matrix”
X O O X
O X X X
X O X X
? ? ? ?
I have found several logical answers in addition to the single “official” answer provided in the book.
I request you solvers to follow suit and to justify all your choices.
Source: will be provided later.
Mensa encourages "out-of-the-box" thinking. Here's one:
Regarding this as a matrix, we can get from row 1 to row 2 by reversing the first 3 symbols (X for O and vice-versa), leaving the 4th coulmn unchanged.
Then, go from row 2 to row 3 by reversing the first 2 symbols, leaving the rest unchanged.
Logically, then, go from row 3 to row 4, by reversing just the first symbol and leaving the rest unchanged.
That gives the last line as O O X X.
Now, I shall return to my box . . . :-)