PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the linex mode where left click+drag draws lines and right click marks X’s)

Theme: Dominoes — in both the clues and the variation rules

Rules: Standard Cave rules. Also, the exterior of the cave (the cells not seen by the numbers) must be divisible into dominoes (1×2 rectangles) in at least one way.

Answer String: Enter the length in cells of each of the cave segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 4:15, Master = 9:00, Expert = 18:00

Solution: PDF

Note: Follow this link for other classic Caves. If you are new to this puzzle type, here are our easiest Cave Puzzles to get started on.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the linex mode where left click+drag draws lines and right click marks X’s)

This is a “Franken-Friday” puzzle variation.

Theme: Prime Time

Rules: Standard Cave rules, except the grid is hexagonal.

Answer String: Enter the length in cells of each of the internal cave segments following the arrows for the marked rows, starting at the top. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 6:00, Master = 8:30, Expert = 17:00

Solution: PDF

Note: Follow this link for other classic Caves. If you are new to this puzzle type, here are our easiest Cave Puzzles to get started on.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the linex mode where left click+drag draws lines and right click marks X’s)

This is a “Twisted Tuesday” puzzle variation.

Theme: Hidden Clues

Rules: Standard Cave rules. Also, no number may directly connect to/”see” another number within horizontally or vertically connected cells.

Answer String: Enter the length in cells of each of the cave segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 2:15, Master = 3:00, Expert = 6:00

Solution: PDF

Note: Follow this link for other classic Caves. If you are new to this puzzle type, here are our easiest Cave Puzzles to get started on.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the linex mode where left click+drag draws lines and right click marks X’s)

This is a “Franken-Friday” puzzle variation.

Theme: Common Products

Rules: Variation of Cave rules. Each clue represents the product of the # of row cells visible (including the cell itself) with the # of column cells visible (including the cell itself).

Answer String: Enter the length in cells of each of the cave segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 3:00, Master = 4:45, Expert = 9:30

Solution: PDF

Note: Follow this link for other classic Caves. If you are new to this puzzle type, here are our easiest Cave Puzzles to get started on.