#71 Grid: Covariance monsters

Grid: Covariance monsters

Prepare a grid. Draw something simple in the upper left cell, such as a smiley face. Draw a similar face in the second cell of this row, but with a difference, for example, adding another eye. In the third cell, add yet another eye. Make predictable changes from one cell to the next. Now work by columns, changing something else, for example, adding horns.

Offer someone who has not seen your grid yet to guess how it works. Prepare an empty grid. The guesser asks what is in a cell, and you put the correct entry there. This game is similar to word-guessing games, where guessers uncover letters. Guessers uncover cells until they can deduce the whole grid.