This style, whose name means “Triangular Numbers” in English and has also been called “Four Directions Loop” elsewhere, was originally created by the Indian team that organized the 2017 World Puzzle Championship as part of an instructionless team round. More Mukkonn Enn will be in our upcoming Loop Variety Collection 2.

PDF

or solve online (using our beta test of Penpa-Edit tools in default linex mode where left-click+drag draws line and right click marks X’s)

Theme: Sequences

Author/Opus: This is the 386th puzzle from our managing editor Serkan Yürekli.

Rules: Draw a single, non-intersecting loop that passes through the center of all cells, including clue cells; the loop may either go straight through or turn at each clue. Each clue cell is divided into four sections; if a number is present in a section and the loop travels in that direction, then the number represents the length of the straight loop segment in that direction, measured from the clue cell to the cell where the loop turns. If the loop does not travel in that direction, then the number means nothing.

Also see this example:

Difficulty: 1 star

Time Standards (highlight to view): Grandmaster = 0:45, Master = 1:00, Expert = 2:00

Solution: PDF and solving video.

Note: Follow this link for other Loop/Path puzzles. More Mukkonn Enn puzzles are in the book Loop Variety Collection 2.

PDF

or solve online (using our beta test of Penpa-Edit tools; use the tab key to alternate between shading, number entry, and composite loop drawing modes)

Theme: Parquet

Author/Opus: This is the 23rd puzzle from guest contributor Bryce Herdt.

Rules: Variation of Nanro rules. Label some cells with numbers to form a single non-intersecting loop; no 2×2 group of cells may be fully labeled, but the loop may touch itself orthogonally or diagonally. The region boundaries divide the loop into segments, and each region must have at least one segment. Numbers denote the length in cells of each segment within a region; all numbers in a region must be the same. When two numbers from different segments are orthogonally adjacent, the numbers must be different. (Consequently, segments in the same region must not share an edge.)

Also see this example:

Difficulty: 4 stars

Time Standards (highlight to view): Grandmaster = 6:15, Master = 9:15, Expert = 18:30

Solution: PDF and solving video.

Note: Follow this link for Nanro puzzles on this website and this link for variations on Nanro puzzles. If you are new to this puzzle type, here are our easiest Nanro Puzzles to get started on. More Nanro puzzles can be found in A Number o’ Nanro by Prasanna Seshadri.

PDF

or solve online (using our beta test of Penpa-Edit tools; use the tab key to alternate between shading, number entry, and composite loop drawing modes)

Theme: Clockwise

Author/Opus: This is the 21st puzzle from guest contributor Bryce Herdt.

Rules: Variation of Nanro rules. Label some cells with numbers to form a single non-intersecting loop; no 2×2 group of cells may be fully labeled, but the loop may touch itself orthogonally or diagonally. The region boundaries divide the loop into segments, and each region must have at least one segment. Numbers denote the length in cells of each segment within a region; all numbers in a region must be the same. When two numbers from different segments are orthogonally adjacent, the numbers must be different. (Consequently, segments in the same region must not share an edge.)

Also see this example:

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 5:00, Master = 12:30, Expert = 25:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for Nanro puzzles on this website and this link for variations on Nanro puzzles. If you are new to this puzzle type, here are our easiest Nanro Puzzles to get started on. More Nanro puzzles can be found in A Number o’ Nanro by Prasanna Seshadri.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: Diamond

Author/Opus: This is the 19th puzzle from guest contributor Bryce Herdt.

Rules: Draw a single, non-intersecting loop that passes through all cells. The loop must form a 60 degree angle in all the cells with black circles, a 120 degree angle in all the cells with gray circles, and a 180 degree angle (straight segment) in all the cells with white circles.

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 4:15, Master = 7:30, Expert = 15:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for other Loop/Path puzzles.

PDF

or solve online (using our beta test of Penpa-Edit tools; in default edgex mode: left-click+drag draws line, right click marks X on edge, tab shifts to a circle shape drawing mode that can help mark the vertices with different circle choices with another tab going back to default edgex)

Theme: Circular Logic

Author/Opus: This is the 197th puzzle from our contributing puzzlemaster Murat Can Tonta.

Rules: Draw a single, non-intersecting loop that only consists of horizontal and vertical segments between the dots. Numbers inside a cell indicate the number of turns taken by the loop at the four dots around it.

Also, see this example:

Difficulty: 4 stars

Time Standards (highlight to view): Grandmaster = 5:00, Master = 10:00, Expert = 20:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for other Loop/Path puzzles. The puzzle styles featured this week are part of the book Loop Variety Collection by Ashish Kumar and Murat Can Tonta.

PDF

or solve online (using our beta test of Penpa-Edit tools; in default linex mode: left-click+drag draws line, right click marks X on edge)

Theme: Four T’s

Author/Opus: This is the 196th puzzle from our contributing puzzlemaster Murat Can Tonta.

Rules: Draw a single, non-intersecting loop in the grid that passes through all white cells. If a number clue is given in a bold region, that number indicates the total count of cells passed through by the largest connected loop section(s) in the region.

Also, see this example:

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 4:30, Master = 8:00, Expert = 16:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for other Loop/Path puzzles. The puzzle styles featured this week are part of the book Loop Variety Collection by Ashish Kumar and Murat Can Tonta.

PDF

or solve online (using our beta test of Penpa-Edit tools; in default lineox mode: left-click+drag draws line, clicking one time in a cell marks a circle and a second time marks an X)

Theme: Brick Wall

Author/Opus: This is the 66th puzzle from our contributing puzzlemaster Ashish Kumar.

Rules: Draw a single, non-intersecting loop in the grid that enters and exits each bold region exactly once. If a number clue is given in a region, that number indicates the exact number of cells used by the loop in the region. Unused cells cannot be orthogonally adjacent across different regions.

Also, see this example:

Difficulty: 2.5 stars

Time Standards (highlight to view): Grandmaster = 2:45, Master = 3:30, Expert = 7:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for other Loop/Path puzzles. The puzzle styles featured this week are part of the book Loop Variety Collection by Ashish Kumar and Murat Can Tonta.

PDF

or solve online (using our beta test of Penpa-Edit tools; in default linex mode: left-click+drag draws line, right click marks X on edge)

Theme: Wbox

Author/Opus: This is the 195th puzzle from our contributing puzzlemaster Murat Can Tonta.

Rules: Draw a single, non-intersecting loop in the grid that passes through all white cells. If a number clue is given in a bold region, that number indicates the total count of cells passed through by the largest connected loop section(s) in the region.

Also, see this example:

Difficulty: 2 stars

Time Standards (highlight to view): Grandmaster = 1:30, Master = 3:00, Expert = 6:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for other Loop/Path puzzles. The puzzle styles featured this week are part of the book Loop Variety Collection by Ashish Kumar and Murat Can Tonta.

PDF

or solve online (using our beta test of Penpa-Edit tools; in default edgex mode: left-click+drag draws line, right click marks X on edge)

Theme: Twin Tornadoes

Author/Opus: This is the 65th puzzle from our contributing puzzlemaster Ashish Kumar.

Rules: Draw a single, non-intersecting loop that only consists of horizontal and vertical segments between the dots. The arrow clues indicate all the directions (up, down, left, and right) where the nearest loop segments are located when looking from that square.

Also, see this example:

Difficulty: 2 stars

Time Standards (highlight to view): Grandmaster = 1:20, Master = 2:15, Expert = 4:30

Solution: PDF; a solution video is also available here.

Note: Follow this link for other Loop/Path puzzles. The puzzle styles featured this week are part of the book Loop Variety Collection by Ashish Kumar and Murat Can Tonta.

From Prasanna: “This puzzle is meant to be a culmination of 10 years of authoring puzzles. I want to especially thank GMPuzzles for accommodating these special puzzles every year even if it may not have fit the regular schedules. I also see this puzzle as a “reset” of sorts, and I’ll get back to simple ideas to celebrate my next few birthdays, and then see where that takes me. These last 10 years have been a fantastic experience and I’d like to take this moment to thank the puzzle community as a whole for being a huge part of my journey.”

(view directly for a larger image)

PDF

or solve online (using our beta test of Penpa-Edit tools; note that the default puzzle info is too long — even for an url shortener — so copy and paste all the text in this file into the “Load” option in the upper-right of the penpa-edit interface to access.)

Theme: The Journey

Author/Opus: This is the 201st puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Please see first two pages of the PDF for a detailed description of the rules and more background on the theme of the puzzle.

Difficulty: 5 stars?

Solution: PDF