KD Insane 4×5 Caps the Review

KrazyDad Insane v.4, b.10, n.5, the last of the Insane review of 2013 is updated, with findings by Andrew Stuarts Sudokuwiki solver and YT. The solver gives us one of Andrew’s Type 2b UR, an ALS boomerang ANL, and something new, a nest of boomerangs. I continue with a walk through of LPO and a pattern trial that eliminates two patterns of a slice, leaving only the follow up of the revealed pattern.

After a generous bypass, KD Insane 4×5 starts with an overabundance of 1,8 and 9-candidates. If you haven’t looked at the updated post yet, find the Type 2b unique rectangle. There’s a floor to ceiling slink . The Solving Tools page has a UR chart.

Next, 4×5 goes directly to AIC building with a series of boomerangs that fit on one grid, because all but the first is an extension of another. The common infrastructure is an ALS that stays in the path as the solver keeps reaching back to an earlier and earlier starting point.  Directions come with it, if you’re like me, assemble first and read later.

Sudokuwiki treats these as separate findings, each one enabling the last.

Unwilling to be left out, 4×5 had to provide Sudokuwiki an ALS boomerang ANL.  The 8-group of the ALS is one terminal, and group member 8r1c7 is the other terminal. The 8-group has to contain a true 8.

This time, when Sydokuwiki gives up, it’s time to do the freeforms and lettering on four X-panels of Insane 4×5 for a Limited Pattern Overlay, covering X = 3, 4, 5, and 6, with 3, 3, 6, and 4 patterns respectively. Also included is the 7-panel with 2 patterns in a single 7-wing.

The idea is to discover any patterns eliminated, with corresponding candidate eliminations, due to conflicts between patterns. It takes organization, because a pattern is not eliminated unless it conflicts with every pattern of another value. To begin, we have to name every possible pattern of the participating values.

Now every cell of each pattern is examined for conflicts with other values, to be translated into conflicts with patterns of other values.

It’s a Big Data problem, the kind normally done by computer, barely kept humanly possible be restricting the data.

The 2013 post illustrates the conflict tables that keep the books as the scanning is done and gives the readout of eliminated patterns.  It doesn’t quite work on 4×5, but it sometimes does. The process qualifies as a logical solution, as opposed to a trial.

In earlier Insanes, coloring trials were set up with apparent clusters made up of pairs of patterns, effectively testing two patterns at a time. Doing that on the 4-panel, with 3 patterns, the true pattern will eliminate a false pattern paired with it, so a contradiction eliminates both patterns.

One trial, on 4a and 4b reached a contradiction in a lengthy trial, leaving 4c to be installed as the true pattern. One color is wrapped in the follow up, and when it stalls, a remote pair and a lengthy XY-chain ANL collapse all resistance to the solution.

The updated review table, with which you can compare the Insane collection to others reviewed in Sysudoku, is in the post of 10/22/2013.

Next post will have parting comments on contributions of the Insanes to the Sysudoku Guide, and an introduction to the next collection review, Classic Sudoku, Book 30 by James Forest. The review starts with Classic 24 above, and includes every 24th for the preselected 10 review puzzles. Have your version ready.