There are twelve rows and columns, and there are twelve colors. A color can only appear once in any given row or column. Each of the twelve "tokens" (e.g. mary, jordan) must be assigned a color, and they must be paired with each of the twelve colors. The white cells are the ones that need a color assignment, and when all the remaining white cells have been assigned a color and the above constraints are still true, the puzzle is solved. What's already there can't be changed.