We've all seen examples of magic squares. The most common one is a 3x3 square using the integers 1 through 9 in which the sum of each row, column and diagonal totals 15.
Players alternately choose an integer (1 to 9) that has not been previously used and place it in any unfilled cell of a Tic-Tac-Toe board. The goal is to make the sum of each row, column, and diagonal equal to 15.
The Game of Magic Square was written by David Ahl and published as type-in source code in Creative Computing, Vol. 1, No. 2, January/February 1974. The program listing is in BASIC with the note: "In converting...to your dialect of BASIC watch out for multiple statements on a line (indicated by a backslash) and compound IF statements."