Remove the all the cards A,2,3,4,5,6,7,8,9 from a deck of cards. There are four of each value for a total of 36 cards. Can you place the cards into a 6x6 grid such that each row, column, and main diagonal has the same sum, and no card value is repeated in any sum. (Let Ace be a value of 1.)
Perhaps this is too unrestrictive? Can it be solved if we also require that each marked 3x2 rectangle also have the same sum?