Let's practice TicTacToe
Commands are:
1-9 for a position
U-n where n is the number of moves to undo
Q to end

1 | 2 | 3
---------
4 | 5 | 6
---------
7 | 8 | 9

Move 1 for X: 5

1 | 2 | 3
---------
4 | X | 6
---------
7 | 8 | 9

Move 2 for O: 3

1 | 2 | O
---------
4 | X | 6
---------
7 | 8 | 9

Move 3 for X: 1

X | 2 | O
---------
4 | X | 6
---------
7 | 8 | 9

Move 4 for O: 6

X | 2 | O
---------
4 | X | O
---------
7 | 8 | 9

Move 5 for X: 9

X | 2 | O
---------
4 | X | O
---------
7 | 8 | X

Move 6 for O: U-2

X | 2 | O
---------
4 | X | 6
---------
7 | 8 | 9

Move 4 for O: 9

X | 2 | O
---------
4 | X | 6
---------
7 | 8 | O

Move 5 for X: 6

X | 2 | O
---------
4 | X | X
---------
7 | 8 | O

Move 6 for O: 4

X | 2 | O
---------
O | X | X
---------
7 | 8 | O

Move 7 for X: 2

X | X | O
---------
O | X | X
---------
7 | 8 | O

Move 8 for O: 7

X | X | O
---------
O | X | X
---------
O | 8 | O

Move 9 for X: 8

X | X | O
---------
O | X | X
---------
O | X | O

Move 10 for O: Q
Thanks for playing!