I claim the ornamental design for a tic-tac-toe game, as shown and described.
FIG. 1 is a perspective view of a tic-tac-toe game showing my design;
FIG. 2 is a side elevational view of one of the sides of the game of FIG. 1, the other four sides being identical; and,
FIG. 3 is a top perspective view of the game of FIGS. 1 and 2, viewed from a location slightly offset from the plane of the side of the game shown at the right of FIG. 3.
The broken line showing is for illustrative purposes only, and forms no part of the claimed design.