+ * - reports from users are that `Trivial'-mode puzzles are still
+ * rather hard compared to newspapers' easy ones, so some better
+ * low-end difficulty grading would be nice
+ * + it's possible that really easy puzzles always have
+ * _several_ things you can do, so don't make you hunt too
+ * hard for the one deduction you can currently make
+ * + it's also possible that easy puzzles require fewer
+ * cross-eliminations: perhaps there's a higher incidence of
+ * things you can deduce by looking only at (say) rows,
+ * rather than things you have to check both rows and columns
+ * for
+ * + but really, what I need to do is find some really easy
+ * puzzles and _play_ them, to see what's actually easy about
+ * them
+ * + while I'm revamping this area, filling in the _last_
+ * number in a nearly-full row or column should certainly be
+ * permitted even at the lowest difficulty level.
+ * + also Owen noticed that `Basic' grids requiring numeric
+ * elimination are actually very hard, so I wonder if a
+ * difficulty gradation between that and positional-
+ * elimination-only might be in order
+ * + but it's not good to have _too_ many difficulty levels, or
+ * it'll take too long to randomly generate a given level.
+ *