Tag Archives: POM

LPO vs Unsolvable 40


This post applies Limited Pattern Overlay, the sysudokie’s POM, to an Andrew Stuart Unsolvable, #40. The interplay of coloring and LPO patterns ties this beast up for the kill. Here is the grid as we apply LPO: My freeform LPO … Continue reading

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Toxic ALS in Unsolvable 40


Our struggle with Unsolvable 40 continues with a detailed walk through of the search for ALS toxic sets, and an analysis of the its stuck number ALS. Here is our grid with row ALS superimposed on a thin, as yet … Continue reading

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Advancing to LPO on Unsolvable 40


This post confirms the intractability of Andrew Stuart “Unsolvable #40” to SSOB  bv scan, X-panel analysis, coloring.  In preparation for Limited Pattern Overlay, a shortcut AIC reduces the number of patterns  for the number 8, and a coloring cluster is … Continue reading

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A Limited Pattern Overlay on Maestro 22


This post details the LPO enumeration and pattern overlay on Maestro 22. To sysudokies working on this over the last posts, the slinks between  7 –candidates suggests coloring.  Every 7-candidate belongs to the cluster.  With no XY-chain, SdC , APE … Continue reading

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Pattern Enumeration for POM and LPO


Pattern overlay methods, both the computer based POM and the human engineered LPO, depend on finding every pattern for each participating number.  Andrew Stuart’s The Logic of Sudoku,   Chapter 32, gives examples of enumerated patterns which demonstrate that candidates can be … Continue reading

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LPO, a Limited Form of POM


The Pattern Overlay Method, or POM is frequently cited as a computer solving method, but seldom proposed as a human solving technique, and for good reason. A pattern is a subset of X-candidates that fit together to provide an X-clue … Continue reading

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