Office: PM 465 Email: email@example.com
You might want to try the Catscan game. You can get a copy here.
In the Catscan game, we have a design hidden behind a 12x12 grid of blank squares. For each row, column and diagonal, we have the number of squares that are full. The idea is to deduce which squares are full. You can look at the underlying picture with "Reveal". You can use a design created at random or one from the file. (Some of the ones in the file are pretty easy.)
If you try it, let me know what you think of it.