Practice
Practice sets.
Twenty-four marshes with no date attached, three sets per level. They never change, so you can come back to one, and they do not touch your daily streak. Your progress in each set stays in this browser.
Easy.
Five by five. Every marsh here opens with the simple steps Hint knows: a nest with only one way out, and a cell whose only free side settles which path must run through it.
Medium.
Six by six. The path you have already drawn starts narrowing which cell a pair can still reach, and Hint reasons from it the same way it reasons from the nests alone.
Hard.
Seven by seven. More passes of local reasoning, and the corners settle one at a time, before the marsh opens up.