
USAGE: undo [n]

Here's an example: suppose you are playing White and your opponent
has just placed a piece on a point where it can be easily captured.
Your opponent might realize the weak move he/she made and request an
undo. You would simply type "undo" to undo their move.

In teaching and fteaching games, a player can specify a number, like:

  undo 5

and that will undo the last 5 moves.

