As mentioned previously, a Fluke check on

DAJ's 7s grid confirmed that all 25 potential remote fins can see the CEC at r9c5. The 25 network diagrams are not listed here (more typing yet to do), but one remote cell (r4c3) was of particular interest because it was very difficult for me to develop its network diagram.

DAJ's grid follows, with (-) marking the CEC.

- Code: Select all
` . 7 . | . 7 . | . . 7`

7 . . | . 7 7 | 7 . .

. . . | 7 . . | 7 . 7

---------+----------+---------

. . 7 | . 7 . | . 7 .

. . 7 | 7 . . | . 7 7

. 7 . | . 7 7 | 7 7 7

---------+----------+---------

. 7 7 | . 7 . | 7 . .

. . . | 7 . . | . 7 7

7 . . | 7 -7 7 | . 7 .

The final network diagram for the remote cell (r4c3):

- Code: Select all
` r5c4----------- r1c5 => r9c5<>7`

|| \ ||

r4c3-r5c3 r8c4-r3c4=r3c79-r1c9

|| || / ||

r5c8-----r8c8 / r1c2-r2c1=r9c1 => r9c5<>7

|| || /

|| r8c9---------

|| /

r5c9---------------

The problem initially was that I kept building implication streams that led to contradictions.

JC Van Hay then offered up the following clever and very compact “hybrid” stream:

r4c3-r5c3=FSF(r358)-r1c9=Kite(r1c1)-r9c5.

FSF(r358) is a finned Swordfish:

3-Fish r358\c489 + fr3c7 => r1c9<>7.

The Kite then completes the CEC elimination as a bidirectional AIC:

r1c5=r1c2-r2c1=r9c1 => r9c5<>7.

I would certainly not have known to look for that finned 3-Fish, but I always find it interesting how

arcilla's lists can spot Fish patterns right off. Numbers shown below are the CPR list's columns per row-position. R4c3 appears as the “3” in r4's (358), and r4c3's five peers are shown bolded:

CPR: (259)(1567)(479)(3

58)(

3489)(

256789)(2

357)(489)(14568)

After removing the five peer candidates (since r4c3 will be assigned as true), the list becomes:

(259)(1567)(

479)(3)(

489)(56789)(257)(

489)(14568)

One can now easily recognize that the underlined column-elements form the

arcilla-equivalent of an ALS, where (7) is the spoiler, and the (489) triple is the LS. This immediately translates to:

3-Fish r358\c489 + fr3c7, which then eliminates r1c9.

The 3-Fish was used to generate the network diagram shown above. Everything to the right of “r4c3” and up through “r1c9” is actually the 3-Fish and its elimination. The strong-inference sets (SIS) plus the one strong-inference link define the base sectors, while the weak-inference links define the cover sectors. The fin is included in the r3c79 node.

OK,

bottom line after reviewing all the evidence:

It's pretty obvious that

JC's hybrid stream makes my network diagram look like a bunch of big

SISsies! But, you gotta ask how

JC found that 3-Fish!