I have a question about the April 19 - 25, 2013, Classic Tic-Tac-Logic 10x10. Is there an error? The top row and the leftmost column are identical. I thought all rows and columns were supposed to be unique.
According to my interpretation the rows are all different from each other and the columns differ from each other.
If the puzzle could not have identity between one row and one column, shoudd we also consider directions? Columns usually are read from top to bottom, but rows can be read from left to right, or vice versa!