Tag Archives: pattern overlay

LPO Lettering on Insane 495


Advanced methods are exhausted on Insane 495 as I review the Insane collection on http://www.krazydad.com.  Basic solving results were reported on the previous post. This post demonstrates a new combination of LPO pattern slicing and pattern conflict analysis that gets … Continue reading

Posted in Extreme Solving, KrazyDad, Puzzle Reviews | Tagged , , , , , | Leave a comment

Unsolvable 40 is Solved?


In the last post, Unsolvable 40 was staggered by a remarkable combination of coloring and LPO.  Only one pattern, 8b, was removed by LPO conflicts.  But other conflicts combined to force another pattern 8c to the color blue in an … Continue reading

Posted in Extreme Solving | Tagged , , , | 1 Comment

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

Posted in Extreme Solving | Tagged , , , , , | Leave a comment

Coloring LPO


We follow up the LPO attack on Maestro 22 in this post to illustrate how coloring enhances LPO pattern enumeration. The clues from pattern 7a  yield N8=>NEhs8=>NEr3np46=> NWr3np89=>Nr3np69, and E9m=>SE9m.  The 5 patterns yield a 5-clue in E. The 2-panel … Continue reading

Posted in Extreme Solving | Tagged , , , , | Leave a comment

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

Posted in Extreme Solving | Tagged , , , | 4 Comments

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

Posted in Extreme Solving | Tagged , , , , , | Leave a comment

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

Posted in Extreme Solving | Tagged , , | Leave a comment