The two Rubik-like puzzles, Sixteen and Twiddle, now support an

The two Rubik-like puzzles, Sixteen and Twiddle, now support an
additional configuration parameter, which is the number of shuffle
moves. By default the grid will be fully shuffled so that you need a
general solution algorithm to untangle it, but if you prefer you can
request a grid which has had (say) precisely four moves made on it,
and then attempt to exactly reverse those four moves.

Currently this feature is only available from the Custom box, and
not in any presets.

[originally from svn r5769]