Snake Pit by Carl Worth

Snake Pit by Carl Worth

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Example puzzle as PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between a composite mode for line/edge drawing and a number entry mode.)

Theme: Logical

Author/Opus: This is the 18th puzzle from our newest contributing puzzlemaster Carl Worth.

Rules: (Hybrid of Fillomino and Snake Puzzles.) Divide the grid along the boundary lines so that every cell belongs to a snake. A snake is a one-cell-wide path at least two cells long that does not touch itself, not even diagonally. Circled cells must be at one of the ends of a snake. A snake may contain one circled cell, two circled cells, or no circled cells at all. Numbered cells must be part of a snake with a length of exactly that number of cells. A snake may contain one number, multiple identical numbers, or no numbers at all. Two snakes of the same length cannot touch each other horizontally or vertically.

Also see this example:

Snake Pit by Carl Worth

Answer String: For each cell in the marked rows/columns, enter the length of the snake it belongs to. Enter just the last digit for any two-digit number. This example has the key “35522,44462”.

Time Standards (highlight to view): Grandmaster = 11:30, Master = 22:00, Expert = 44:00

Solution: PDF

Note: Follow these link for other Fillomino or Snake puzzles.

  • Loren R says:

    I am a little behind solving puzzles. Thank you Carl for this new puzzle type!

  • Carl W says:

    You’re quite welcome, Loren. I’m glad you enjoyed these.

    And do stay tuned for more to come in the future.


  • Poony says:

    I have no idea how to get started…
    Feel free to encrypt it.

  • Carl W says:

    Hi Poony, thanks for reaching out for some help. I enjoyed writing this since it forced me to re-solve this puzzle, (and of course, I had forgotten some of the starting steps).

    I confess, this puzzle is particularly challenging to get started. So I apologize in advance for the length of this comment. The rot13 text that follows is a walkthrough that should get you going on this puzzle.

    Of course, feel free to stop at any point and work the rest from there. And happy puzzling!

    V’yy fubj gur beqre bs gur svefg frireny qrqhpgvbaf V hfr va zl fbyivat cngu sbe guvf chmmyr. Rnpu bar bs gurfr pna or neevirq ng jvgu evtbebhf ybtvp, (fbzrgvzrf jvgu fbzr snveyl pnershy nppbhagvat bs ninvynoyr fdhnerf). Vs lbh svaq gung pbhagvat naablvat (V bsgra qb jura fbyivat chmmyrf) V jba’g oynzr vs lbh whfg hfr fbzr vaghvgvba nebhaq gur pebjqrq cnegf bs gur chmmyr naq whfg fnl “Vg’f tbg gb or yvxr guvf, evtug?”. Punaprf ner (jvgu guvf chmmyr) lbh’yy or evtug.

    Fb guvf jvyy or n fxrgpu bs gur ortvaavat bs gur fbyhgvba, jvgubhg n shyy rkcynangvba bs rirel cbvag. Vs lbh jnag nal zber qrgnvyf ng nal cbvag, yrg zr xabj.

    Gurer ner ng yrnfg n pbhcyr bs cbvagf jurer gur fbyhgvba uvtuyvtugf n trareny grpuavdhr gung V guvax vf vagrerfgvat. V’yy pnyy gubfr bhg jvgu nfgrevfxf yvxr guvf (***).

    Svefg, pbafvqre gur svefg rvtug pvepyrq fanxr raqf ba gur hccre cbegvba bs gur F funcr, (nyy bs juvpu unir ynetr ahzoref). Ubj znal pbhyq cebprrq gb gur vagrevbe bs gur hccre cbegvba bs gur F? Gurer ner bayl guerr rkvgf sbe fanxrf gb gur evtug, (gjb orgjrra gur 5 naq 4, naq n guveq orgjrra gur 4 naq 19). Fb ng zbfg, guerr bs gurfr rvtug fanxrf tb vafvqr gur F urer.

    Abj, pbafvqre ubj yvggyr fcnpr gurer vf ba gur yrsg fvqr bs gur F. Bar fanxr pbhyq rkvg nybat gur gbc, ohg tvira gur yvzvgrq nzbhag bs fcnpr erznvavat, gur pvepyrq 14, 20, naq 21 fanxrf zhfg pbaarpg gb gurve zngpuvat hapvepyrq ahzoref.

    Tvira gung, gur fcnpr va gur ybjre cbegvba bs gur F vf fb pbafgenvarq gung gur pvepyrq 9 naq 15 zhfg tb vagb gur hccre cbegvba bs gur F.

    Naq tvira gur yvzvgrq fcnpr va gur hccre-yrsg bs gur chmmyr, bar bs gur hccre 12, 15, naq 19 zhfg or gur guveq naq ynfg fanxr gb tb vafvqr gur hccre cbegvba bs gur F, (naq bar bs gur 15 be 19 zhfg rkvg nybat gur gbc bs gur chmmyr).

    Abj jr pna fgneg qenjvat gur fanxr bs gur ybjre pvepyrq 15.

    Jr xabj vg fgneg bss ol tbvat hc bar fdhner. Vs vg pbagvahrf hc gjb zber fdhnerf (gb gur yrsg bs gur 2) vg jvyy cvapu bss gur 9. Ohg pbhyq vg cebprrq hc bar nqqvgvbany fdhner naq gura cebprrq evtug gb gur fdhner whfg gb gur yrsg bs gur gjb?

    (***) Urer’f n pbby ybtvp fgrc gung zvtug or hfrshy va bgure fanxr chmmyrf. Juvyr vzntvavat n fanxr cebprrqvat hc gjb fdhnerf sebz gur ybjre-pvepyrq 15 naq gura gb gur evtug, pbafvqre gur rzcgl fdhner gung jbhyq or vfbyngrq whfg nobir gur 14. Vs n fdhner vf phg bss sebz guerr fvqrf yvxr guvf, vg zhfg gura rkgraq bhg gur 4gu fvqr, (fvapr rirel fdhner zhfg orybat gb n fanxr naq rirel fanxr vf ng yrnfg gjb pryyf ybat).

    Guvf arj fanxr jbhyq gura sbepr gur 15 fanxr orgjrra gur 2 naq gur 4. Ohg gung jbhyq znxr vg vzcbffvoyr gb pbzcyrgr obgu gur 9 naq gur guveq ynetr fanxr va guvf hccre cbegvba bs gur F.

    Fb gur ybjre-15 fanxr zhfg cebprrq vzzrqvngryl evtug, hfvat gur fdhner whfg nobir gur 15. Fvzvyne ybtvp cebirf gung vg zhfg pbagvahr evtug hfvat gur fdhner nobir gur 4.

    Guvf vf n pevgvpny fgrc fvapr vg sbeprf gung 4 gb rkgraq qbja, juvpu yrgf hf erfbyir fbzr vzcbegnag guvatf nobhg gur 14 orybj.

    (***) Ohg orsber jr trg gb gung 14, yrg’f ybbx ng nabgure trareny grpuavdhr. Guvf vf n cnevgl gevpx jvgu fanxr yratguf. Vzntvar n fanxr ba n purpxreobneq, fgnegvat ba n oynpx fdhner. Nf gung fanxr tebjf, jurarire vg vf na rira yratgu vg jvyy or ba n juvgr fdhner, naq jurarire vg vf na bqq yratgu, vg jvyy or ba n oynpx fdhner. Nabgure jnl gb guvax bs guvf ehyr vf gung vs lbh unir nal fanxr cngu orgjrra gjb cbvagf, nal zbqvsvpngvba lbh znxr gb gur cngu zhfg punatr gur fanxr’f yratgu ol na rira ahzore, vg pna arire punatr vg’f yratgu ol na bqq ahzore.

    Guvf ehyr pna or chg gb terng hfr urer. Vzntvar nal cngu lbh’q yvxr sebz gur pvepyrq 21 gb gur bgure 21 naq pbhag gur fdhnerf va gur cngu. Lbh tbg na rira ahzore, evtug? Ohg jr xabj guvf fanxr unf na bqq yratgu (21). Gung zrnaf gur hapvepyrq 21 pnaabg or gur raq bs gur fanxr, ohg zhfg hfr ng yrnfg bar zber fdhner.

    Nyfb, abgvpr gung gur cnguf bs gur yratgu-20 naq yratgu-21 fanxrf pnaabg pebff rnpu bgure. Gung zrnaf gur cngu bs gur yratgu-21 fanxr zhfg ragre gur hapvepyrq 21 sebz gur yrsg naq zhfg pbagvahr sebz gurer gb gur pryy nobir.

    Jvgu gubfr gjb fdhnerf pynvzrq, jr pna pbafvqre gur hapvepyrq 20. Urer, jvgu gur 14 nyernql rkgraqvat qbja ng yrnfg bar fdhner, naq jvgu gung 3 naq gur arneol pvepyr va gur jnl, gurer’f whfg abg ebbz sbe gur yratgu-20 fanxr gb svg vafvqr gur yratgu-21 fanxr hayrff vg nyfb ragref gur hapvepyrq 20 sebz gur yrsg naq pbagvahrf sebz gurer gb gur pryy nobir.

    Univat gur yratgu-20 naq yratgu-21 fanxrf pynvz rnpu bs gur pryyf nobir gurz vf pevgvpny sbe abj qrqhpvat gur cngu bs gur yratgu-14 fanxr. Abgr gung ertneqyrff bs gur cngu vg gnxrf vg zhfg rvgure ragre be rkvg gur ybjre cbegvba bs gur ovt F funcr ba n ubevmbagny yvar hfvat gur fdhner vzzrqvngryl orybj gur 3.

    Naq tvira gung vg’f hfvat gung fdhner, nsgre gur fanxr tbrf qbja sebz gur pvepyrq 14 vg pnaabg tb qbja ntnva be ryfr vg jvyy gbhpu vgfrys qvntbanyyl (tvira obgu gur hapvepyrq 14 naq gur fdhner jr whfg qrqhprq orybj gur 3).

    Fb vg zhfg cebprrq gb vapyhqr gur fdhner nobir gur 3.

    Gura, vg pnaabg arkg tb qbja orgjrra gur 3 naq gur arneol pvepyr be vg jba’g unir ebbz gb pbzcyrgr vgfrys orsber gbhpuvat vgfrys. Fb vg zhfg hfr gur fdhner nobir gur pvepyr.

    Ng guvf cbvag, gurer’f bayl bar cbffvoyr cngu sbe gur yratgu-14 fanxr, cebprrqvat pbhagre-pybpxjvfr nebhaq gung pvepyr nf gvtugyl nf cbffvoyr naq neevivat ng gur hapvepyrq 14, (n cngu bs yratgu 13 yrnivat whfg bar zber pryy gb or qrgrezvarq.

    Naq abgr gung guvf cngu vfbyngrq guerr qvssrerag fdhnerf va qrnq raqf, (gur fdhner orybj gur pvepyrq 9, gur pvepyrq fdhner arne gur 3, naq gur fdhner gb gur hccre-yrsg bs gur hapvepyrq 21). Nyy guerr bs gurfr fdhnerf pna abj or qenja nf fanxrf bs ng yrnfg yratgu 2 sbe abj.

    Guvf yrnirf bayl bar cbffvovyvgl sbe gur ohyx bs gur cnguf bs gur yratgu-20 naq yratgu-21 fanxrf. Fb znal bs gubfr pna or qenja va, (fgnegvat ng gur hapvepyrq ahzoref, lbh pna qrgrezvar rirel fdhner va rnpu fanxr rkprcg sbe gur ynfg bar nf lbh jbex onpx gbjneq gur pvepyrq ahzoref).

    Curj! Ng gung cbvag, V guvax gur chmmyr vf ernyyl fgnegrq, naq ubcrshyyl lbh’yy or noyr gb cebprrq sebz urer.

    Ohg yrg zr xabj vs lbh arrq nalguvat shegure.

  • Poony says:

    Thank you so much. I finally solved it by logic. Although this is the only puzzle I stuck on this week’s snake pit puzzle. I enjoy all of them. Again, thank you for these briliant puzzles.

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