... are pretty simple. At the top of the puzzle there is a message box displaying what has just been done. There is a 'Load' drop down box which can be used to load one of a number of pre-defined puzzles. To clear the puzzle load the pre-defined 'blank' puzzle.
There are also two buttons:-
Solve – Calls 'Process' repeatedly until the puzzle either solves or fails.
Process – Carries out one stage of processing.
There are also a set of controls for each square. These consist of :-
A drop down box. This displays the squares value, if known, or zero if the value is unknown. Once the puzzle has been cleared these boxes can be used to set up it's starting state. They can also be used to 'tinker' with it's state during the solving process.
A tick box. This indicates if something in the square's row, column or box changed during the last stage of processing. i.e. If the squares value is to be recalculated during the next phase.
A bit mask displaying the values that the square could contain. For example if the square could have value 5, 3 or 2 the bitmask would show 000010110. If there is an error then this field is highlighted in red. This will typically because :-
There are no remaining possible values for this square.
The all squares claim to be solved but the sanity checker has detected more than one square, in a bunch, with the same value.
Sometimes you may be able to recover by entering extra information and hitting 'process'. However, in general, “if it's red you're dead.”. Reload 'blank' and try again the correct starting information.