A very old game where each player attempts to place three of their markers (usually an X or an O) in a line on a 3x3 grid. The Romans called this game Terni Lapilli (this does not appear to be true, Terni Lapilli seems to be a distinct and separate game). It shares the board but the players only have 3 pieces each. The same game may be played not on the grid spaces but on lines where it is aka Three Men's Morris.