From the Foxger’s Den #43: Cross the Streams (Inverted)
or solve online (using our beta test of Penpa-Edit tools)
This is a “Twisted Tuesday” puzzle variation.
Theme: Inverted Clues
Rules: Variation of Cross the Streams rules. The clues in this puzzle are inverted. They indicate the WHITE (unshaded) areas, not the black areas as in other Cross the Streams. The shaded cells must still obey the regular rules (connectivity, no 2×2 squares).
Answer String: Enter the length in cells of each of the black segments from top to bottom for the marked columns, going in order from A to B to C to D and separating each entry with a comma.
Time Standards (highlight to view): Grandmaster = 2:15, Master = 3:30, Expert = 7:00
Solution: PDF
Easy but charming.
The back and forth between having the 2×2 rule and the clues forcing some barriers of white, and then squirting the black around the corners for connectivity is fun. That dynamic gives the puzzle a bit of a nurikabe feel.
I have to keep telling myself that while the clues are inverted, connectivity isn’t.
01:35. A few seconds because I have to keep telling myself that while clues are inverted, connectivity isn’t— oh, screw it.
Nice puzzle. The juggling of making the black follow the usual connectivity/2×2 rules and satisfying clues of white makes much single paths everywhere, making it a fairly straightforward solve. But hey, the idea is neat (and mathgrant indeed did it before) and it’s Tuesday.