Here's a shot at a description for Frankenfish. Corrections are always appreciated.
Frankenfish came about as a result of studies of larger fish (whales, etc) started by vidarino
here. The conclusion of this study was that if two rows or columns of a fish share the same band or stack, then elimination with bigger fins are possible than could otherwise occur. In the following example, if the two rightmost columns were in separate stacks the elimination could not occur. An elimination is possible because the fish's "big fin" which is located in a single box. This is characteristic of Frankenfish: larger fins which are located in one or more boxes. Recognition of a Frankenfish allows for an elimination with a smaller fish than would otherwise be possible. As a result the largest fish currently identified is a Mutant Squirmbag.
- Code: Select all
Finned Franken Swordfish: ccc/rrbf
. . . | . / . | X X .
. . . | . # . | X X *
. . . | . / . | X X .
------+-------+------
. . . | . / . | / / .
. . . | . X . | X X .
. . . | . / . | / / .
------+-------+------
. . . | . / . | / / .
. . . | . / . | / / .
. . . | . X . | X X .
If certain cells of the fish do not contain the fish digit then more eliminations are possible. This led to Havard's discovery of the
Frankenfish. Rkral demonstrated an even earlier version of
this fish. In the following example of a Finless Franken Swordfish, eliminations can occur in two rows and one box. This is different from a basic swordfish where eliminations occur in three rows if the fish is defined by columns and three columns if defined by three rows. Franken fish eliminations occur because the fish digits in the "n" columns (rows) of the fish can also be contained in (covered by) a total of "n" rows and/or boxes (columns and/or boxes). This is the concept of constraint subsets which is further described in the Mutant Fish post.
- Code: Select all
Finless Franken Swordfish: ccc/rrb
. . . | . / . | X X *
. . . | . / . | X X *
. . . | . / . | X X *
------+-------+------
. . . | . / . | / / .
* * * | * X * | X X *
. . . | . / . | / / .
------+-------+------
. . . | . / . | / / .
* * * | * X * | X X *
. . . | . / . | / / .
Fish with elimination in more than one box are possible resulting in the "skinny" jellyfish in this example:
- Code: Select all
Finless Franken Jellyfish: cccc/rrbb
. . . | * X X | X X *
. . . | * X X | X X *
. . . | * X X | X X *
------+-------+-------
. . . | . / / | / / .
* * * | * X X | X X *
. . . | . / / | / / .
------+-------+-------
. . . | . / / | / / .
. . . | . / / | / / .
* * * | * X X | X X *
There are two other types of finned Franken Swordfish, where the second is also an empty rectangle.
- Code: Select all
Finned Franken Swordfish: ccc/rrbf
. . . | . / . | X X .
. . . | . / . | X X .
. . . | . / . | X X .
------+-------+------
. . . | . # . | / / .
. . . | * X * | X X .
. . . | . # . | / / .
------+-------+------
. . . | . / . | / / .
. . . | . / . | / / .
. . . | . X . | X X .
Finned Franken Swordfish: ccc/rrbf
. . . | . / . | X X .
. . . | . / . | X X .
. . . | . / . | X X .
------+-------+------
. . . | . / . | / / .
. . . | . X . | X X .
. . . | . / . | / / .
------+-------+------
. . . | . / . | # # .
. . . | . / . | # # .
. . . | . X . | X X *
Originally Franken Fish were true fish defined by "n" rows or "n" columns. The definition has been expanded to include a form of Mutant Fish where the fish is defined by a total of "n" rows and/or boxes or a total of "n" columns and boxes. For example:
- Code: Select all
Finless Franken Swordfish: rrb/ccc
. . . | . * . | X X /
. . . | . * . | X X /
. . . | . * . | X X /
------+-------+------
. . . | . * . | * * .
/ / / | / X / | X X /
. . . | . * . | * * .
------+-------+------
. . . | . * . | * * .
/ / / | / X / | X X /
. . . | . * . | * * .
Exemplars of Franken X-wings (equivalent to locked candidates) and Franken Jellyfish are found in the first post of this thread. If only true fish are considered, then
Franken Squirmbags can be found which do not have smaller fish equivalents. These do have smaller mutant equivalents.