LPO pattern analysis is enlisted in the primary color trial of Hanson and Marans’ Easter Monster.
Two clusters have been constructed by linking the 4/6 slink loops of W and S boxes along with the 3/7 slink loops of the SW and C boxes. Sysudoku prefers Medusa coloring to H & M strong link chains as a representation of the slink field.
The new red/orange cluster traps four candidates and expands further, but the 3 and 7 candidates and blue/green cluster is unaffected.
From this point, Hanson and Barans found red vs orange trials to be “relatively straightforward checking, including almost-locked pair analysis” to decide on red and find the solution. I think we’d better find out how hard that is with Sysudoku tools, starting with an orange trial. I’ll leave it to a sysudokie reader to tell us where the ALS pair removals are.
I’ll start with a pattern analysis of 3, 7, 4 and 6. I freeformed six patterns each for 3, 7 and 6. Fortunately for 4, there were only two. Thus on an orange or red trial, cells can be reserved for the sole 4 pattern. The reservations on behalf of 4 are marked on the other panels, revealing the patterns that these reservations eliminate.
On our orange trial we can eliminate:
3 blue short dashed,
3 green short dashed,
7 blue long dashed,
7 blue short dashed,
7 green short dashed and 7 green long dashed.
On a red trial, we can eliminate 3 blue solid, 3 greenshort dashed, 3 green long dashed, 7 blue long dashed and 7 green solid.
The expansion brings in 8 and 2, but the new blue 2r7c1 goes too far, stripping cell r7c2 of all candidates. Suddenly orange is defended only by green.
The 1-wing, in particular generates a series of unfortunate events for orange.
The W naked pair 28 confirms W1, which turns on C8, C5, and C1. C5 enables the S naked pair 29 to strip a 2, and it strips a 5, from r1c5. And C1? It confirms E1, rejecting the long dashed pattern and with it, the last remaining candidate in r1c5.
So we have accomplished H & M’s “relatively simple matter” getting us to the orange color wrap. Next time, we’ll use it to get to the solution of the HM Easter Monster.
Or maybe you’re not going to wait that long. Be my guest.