PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between a shading mode, a mode to mark edges with an X, and a letter entry mode that may help with notation.)

Theme: Words

Author/Opus: This is the 232nd puzzle from our contributing puzzlemaster Murat Can Tonta.

Rules: Standard LITS rules. Also, the letters outside the grid indicate the first tetromino encountered in the corresponding direction. Or see this:

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 5:15, Master = 7:15, Expert = 14:30

Solution: PDF and solving video.

Note: Follow this link for more variations of LITS and this link for classic LITS. If you are new to this puzzle type, here are our easiest LITS to get started on. More LITS puzzles can be found in LOTS O’ LITS by Grant Fikes and Prasanna Seshadri, in The Art of Puzzles 2, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between a shading mode and a mode to mark edges with an X.)

Theme: Jigsaw

Author/Opus: This is the 14th puzzle from guest contributor Chris Green.

Rules: Variation of LITS. Some cells or groups of cells are outlined and labeled with a letter. If any of these cells is shaded, then the tetromino shape must match the clued letter.

Difficulty: 2.5 stars

Time Standards (highlight to view): Grandmaster = 3:15, Master = 5:00, Expert = 10:00

Solution: PDF and solving video.

Note: Follow this link for more variations of LITS and this link for classic LITS. If you are new to this puzzle type, here are our easiest LITS to get started on. More LITS puzzles can be found in LOTS O’ LITS by Grant Fikes and Prasanna Seshadri, in The Art of Puzzles 2, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

PDF

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

Theme: Coral Anniversary

Author/Opus: This is the 375th puzzle from our contributing puzzlemaster Grant Fikes.

Rules: Variation of LITS. Shade exactly four cells in each outlined region to form an S, L, I, C, or Y tetrahex. When all regions have been shaded, the following conditions must be true:
1) All shaded cells will be connected through a network of adjacent shaded cells;
2) No three shaded cells will share a common vertex;
3) When two tetrahexes share an edge in adjacent regions, they must not be the same type (S, L, I, C, or Y), regardless of potential rotations or reflections.

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 4:00, Master = 5:00, Expert = 10:00

Solution: PDF and solving video.

Note: Follow this link for more variations of LITS and this link for classic LITS. If you are new to this puzzle type, here are our easiest LITS to get started on. More LITS puzzles can be found in LOTS O’ LITS by Grant Fikes and Prasanna Seshadri, in The Art of Puzzles 2, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

See more discussion of the puzzles from the United States’ 2021 Puzzle Grand Prix on this post. Note there are some construction details and potential spoilers on that post so view it after you solve.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the composite Yajilin mode where left click marks cells, right click marks dots in cells or X’s on edges, left click+drag draws lines.)

Author/Opus: This is the 350th puzzle from our managing editor Serkan Yürekli.

Rules: Standard LITS rules: Shade exactly four connected cells in each outlined region, to form an L, I, T, or S tetromino, so that the following conditions are true: (1) All shaded cells are connected with each other; (2) No 2×2 group of cells can be entirely shaded black; (3) When two tetrominoes in adjacent regions share an edge, they must not be of the same type (L, I, T, or S), regardless of rotations or reflections.

Also, the number clues follow standard Tapa rules: Numbers in a cell indicate the length of consecutive shaded blocks in the neighboring cells. If there is more than one number in a cell, then there must be at least one white (unshaded) cell between the black cell groups. Cells with numbers cannot be shaded.

Difficulty: 1.5 stars (estimate based off competition points; timing standards not available from our usual testers)

Solution: PDF

Note: Follow this link for more variations of LITS and this link for classic LITS. Follow this link for classic Tapa and this link for Tapa variations.

PDF

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

Theme: Five Shurikens

Author/Opus: This is the 36th puzzle from our contributing puzzlemaster JinHoo Ahn.

Rules: Shade some cells black so that in each region there are exactly four unshaded cells that form an L, I, T, S, or O tetromino. When two unshaded tetrominoes share an edge across regions, they must not be the same shape regardless of rotations or reflections. All shaded cells must be connected into a single group, but no 2×2 group of cells can be entirely shaded black.

Example by Thomas Snyder:

Difficulty: 5 stars

Time Standards (highlight to view): Grandmaster = 12:00, Master = 25:00, Expert = 50:00

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

Note: Follow this link for more variations of LITS and this link for classic LITS. If you are new to this puzzle type, here are our easiest LITS to get started on. More LITS puzzles can be found in LOTS O’ LITS by Grant Fikes and Prasanna Seshadri, in The Art of Puzzles 2, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

PDF

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

Theme: Sssssssss

Author/Opus: This is the 7th puzzle from guest contributor Takeya Saikachi.

Rules: Standard LITS rules. Also, the letters outside the grid indicate the first tetromino encountered in the corresponding direction. Or see this:

Difficulty: 2.5 stars

Time Standards (highlight to view): Grandmaster = 2:15, Master = 3:30, Expert = 7:00

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

Note: Follow this link for more variations of LITS and this link for classic LITS. If you are new to this puzzle type, here are our easiest LITS to get started on. More LITS puzzles can be found in LOTS O’ LITS by Grant Fikes and Prasanna Seshadri, in The Art of Puzzles 2, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

PDF

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

Theme: Mini Hexes

Author/Opus: This is the 384th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Variation of LITS. Shade exactly four cells in each outlined region to form an S, L, I, C, or Y tetrahex. When all regions have been shaded, the following conditions must be true:
1) All shaded cells will be connected through a network of adjacent shaded cells;
2) No three shaded cells will share a common vertex;
3) When two tetrahexes share an edge in adjacent regions, they must not be the same type (S, L, I, C, or Y), regardless of potential rotations or reflections.

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 5:00, Master = 8:00, Expert = 16:00

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

Note: Follow this link for more variations of LITS and this link for classic LITS. If you are new to this puzzle type, here are our easiest LITS to get started on. More LITS puzzles can be found in LOTS O’ LITS by Grant Fikes and Prasanna Seshadri, in The Art of Puzzles 2, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

Prasanna is celebrating two milestones this week and we will have two special large puzzles. The first one here recognizes Prasanna’s 200th submission on GMPuzzles, and combines three of the styles where Prasanna has written books for our e-store.

(view directly for a larger image)

PDF

or solve online (using our beta test of Penpa-Edit tools; while solution checking is not enabled, if you are comfortable with the different tool selection options you should be able to fully solve the puzzle in this mode too.)

Theme: Linking 200 cells

Author/Opus: This is the 200th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules:

Grids 1-2: Follow regular LITS rules. Between the two LITS grids, the corresponding white cells can never both be shaded, while the corresponding gray cells must be identical in the three 200-shaped regions.

Use the LITS solutions and your ingenuity to discover the needed constraints for Grids 3-4. For Grid 3, you will find that some gray circles must change color to white or black.

Grid 3: Follow regular Balance Loop rules. Additionally, the loop must cross itself if it passes through a gray circle. The loop must go straight throught the gray circle both times; in one direction the path behaves as if the circle is white with equal loop lengths, and in the other direction the path behaves as if the circle is black with unequal loop lengths. It is not required that the loop pass through all of the gray circles (but it must pass through all white and black circles). (See also the image below.)

Grid 4: Follow regular Yajilin rules.

When taken together, the grids yield a short final answer! Send this (less than five character) string to hiddencontest at gmpuzzles dot com by March 14th, 2021 to be eligible to win an e-book by Prasanna Seshadri. The contest is now closed and results summarized here.

Difficulty: 5 stars?

Solution: PDF

PDF

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

Theme: Double “LITS”

Author/Opus: This is the 22nd puzzle from guest contributor Joseph Howard.

Rules: Standard LITS rules, except that each region must contain two shaded tetrominoes. These two tetrominoes within a region cannot touch each other, and can be the same or different shapes.

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 4:45, Master = 6:45, Expert = 13:30

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

Note: Follow this link for classic LITS and this link for LITS variations. If you are new to this puzzle type, here are our easiest LITS to get started on. More LITS puzzles can be found in LOTS O’ LITS by Grant Fikes and Prasanna Seshadri, in The Art of Puzzles 2, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

This week we are sharing easy sample puzzles from our ebook The Puzzlemasters’ Workshop which showcases six authors exploring new puzzle styles or variations with 8-10 challenges in each section. Today’s post is Inverse LITS.

PDF

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

Theme: Rectangles

Background: Variation of the shading puzzle LITS, where the usual rules related to shaded tetrominoes in each region are inverted to apply to unshaded tetrominoes in each region. First explored by Bram de Laat in 2012, and now more fully explored by Chris Green.

Rules: Shade some cells black so that in each region there are exactly four unshaded cells that form an L, I, T, S, or O tetromino. When two unshaded tetrominoes share an edge across regions, they must not be the same shape regardless of rotations or reflections. All shaded cells must be connected into a single group, but no 2×2 group of cells can be entirely shaded black.

Example by Thomas Snyder:

(No official times or solution entry for this week; just click “SOLVE?” when finished.)

Solution: Last page of PDF

Note: More Inverse LITS puzzles can be found in The Puzzlemasters’ Workshop.