While checking invalidity of the first Blue's 18-clue pattern in the thread Maximal invalid patterns with the fewest number of clues I accidentally discovered new 19-clue minimal pattern by adding 1 clue to the central cell of the grid:
- Code: Select all
Blue1+1
. x . . . . x . .
x . . . . x . . .
. . . . x . . . x
. . . x . . . x .
. . x . x . x . .
. x . . . x . . .
x . . . x . . . .
. . . x . . . . x
. . x . . . . x .
This pattern produces 495 valid puzzles, all are minimal.
This is the first pattern I saw when adding 1 clue transforms maximal invalid pattern to minimal valid pattern.
Serg
