Memo
In the table above, you are able to set memos for the choosen cell.
Click with your mouse or push the blank key to set a memo. Your
memos will be shown as a point in the table and in the cell. A
point upper left means, you think, the symbol 1 is possible here, a
point bottom right means, you think the symbol 9 is possible.
In support level 0, all memos will be shown blue, in support level
1, obvious wrong memos will be shown red.
fixed
If you think, the symbol in the choosen cell is the right one, you
are able to fix the cell. The symbol will be paint in another color
and the cell is no longer editable.
Suggestions
From support level 3, the table show the possibilities based on the
givens.