<Ul> <Li> If O responds with a center mark (best move for them), a perfect X player will take the corner opposite the original . Then O should play an edge . However, if O plays a corner as its second move, a perfect X player will mark the remaining corner, blocking O's 3 - in - a-row and making their own fork . </Li> <Li> If O responds with a corner mark, X is guaranteed to win, by simply taking any of the other two corners and then the last, a fork . (since when X takes the third corner, O can only take the position between the two X's . Then X can take the only remaining corner to win) </Li> <Li> If O responds with an edge mark, X is guaranteed to win, by taking center, then O can only take the corner opposite the corner which X plays first . Finally, X can take a corner to create a fork and then X will win on the next move . </Li> </Ul> <Li> If O responds with a center mark (best move for them), a perfect X player will take the corner opposite the original . Then O should play an edge . However, if O plays a corner as its second move, a perfect X player will mark the remaining corner, blocking O's 3 - in - a-row and making their own fork . </Li> <Li> If O responds with a corner mark, X is guaranteed to win, by simply taking any of the other two corners and then the last, a fork . (since when X takes the third corner, O can only take the position between the two X's . Then X can take the only remaining corner to win) </Li> <Li> If O responds with an edge mark, X is guaranteed to win, by taking center, then O can only take the corner opposite the corner which X plays first . Finally, X can take a corner to create a fork and then X will win on the next move . </Li>

What is the meaning of tic tac toe