Lot of discussion 5 years ago about a.
#24a Advanced problem
$$Bc
$$----------
$$|.O.......
$$|.XOOOX...
$$|.XXXXOOO.
$$|..XXO....
$$|XXXOO....
$$|OOO......
$$|.........
$$----------
$$|.O.......
$$|.XOOOX...
$$|.XXXXOOO.
$$|..XXO....
$$|XXXOO....
$$|OOO......
$$|.........
- Click Here To Show Diagram Code
[go]$$Bc
$$----------
$$|.O.......
$$|.XOOOX...
$$|.XXXXOOO.
$$|..XXO....
$$|XXXOO....
$$|OOO......
$$|.........[/go]
$$Bc
$$--------
$$|OXO.O..
$$|O.OOOX.
$$|..XXXX.
$$|XX.,...
$$|.......
$$--------
$$|OXO.O..
$$|O.OOOX.
$$|..XXXX.
$$|XX.,...
$$|.......
- Click Here To Show Diagram Code
[go]$$Bc
$$--------
$$|OXO.O..
$$|O.OOOX.
$$|..XXXX.
$$|XX.,...
$$|.......[/go]
$$Bc
$$--------
$$|..O....
$$|.OOX.X.
$$|.OXX...
$$|OOX,...
$$|XXX....
$$|.......
$$--------
$$|..O....
$$|.OOX.X.
$$|.OXX...
$$|OOX,...
$$|XXX....
$$|.......
- Click Here To Show Diagram Code
[go]$$Bc
$$--------
$$|..O....
$$|.OOX.X.
$$|.OXX...
$$|OOX,...
$$|XXX....
$$|.......[/go]