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: Sunken Lake
Author/Opus: This is the 54th puzzle from our contributing puzzlemaster John Bulten.
Shade some empty cells black to create a single group of black cells that are all connected to each other through their edges. No 2×2 cell area within the grid contains all black cells. Numbers to the left/top of the grid represent the groups of consecutive black cells which are in that row/column in order, either from left to right or from top to bottom. A question mark (?) represents a group of consecutive black cells whose size is unknown; an asterisk (*) represents any number of unknown groups of black cells, including none at all.
All white cells must be connected via other white cells to an edge of the grid. All numbered cells inside the grid must be white and each number in these cells indicates the total count of white cells connected vertically and horizontally to the numbered cell including the cell itself.
See also this example:
Answer String: Enter the length in cells of each of the (white) 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 = 3:30, Master = 4:30, Expert = 9:00
Note: Follow this link for other Cross the Streams. Follow this link for other Cave variations and this link for other classic Caves. If you are new to Cave puzzles, here are our easiest Cave Puzzles to get started on. More Cave puzzles can be found in The Art of Puzzles and in Roger Barkan’s Colossal Cave Collection.