Here is a small enhancement to playing SuDoKu in Emacspeak. The feature is probably generally useful i.e., it's not specific to eyes-free interaction, but its presence encourages one to try different solution strategies.
Commands emacspeak-sudoku-history-push bound to
m and emacspeak-sudoku-history-pop
bound to M allow one to mark interesting
states in the game and return to these prior states with a single
keystroke. This means that when one is confronted with one of
two choices, with no apparent additional information on which
route to take, it becomes possible to push that state on to the
history stack, try one of the alternatives and backtrack if necessary.
