The Persistence of Memory by Prasanna Seshadri
or solve online (using our beta test of Penpa-Edit tools using a composite mode where left click inside cell shades square, left click + drag draws line segment, right click inside cell adds dot, and right click on cell edge adds an x.)
Theme: Tetrominoes
Author/Opus: This is the 186th puzzle from our contributing puzzlemaster Prasanna Seshadri.
Rules: Draw a snake (a 1-cell wide path) from one dot to the other by moving horizontally or vertically between adjacent squares. The snake cannot touch itself, not even diagonally. All highlighted regions must be visited by the snake, and may be re-entered. If two or more highlighted regions have the same shape and orientation, then how the path passes through those shapes must be identical.
Difficulty: 3 stars
Time Standards (highlight to view): Grandmaster = 4:45, Master = 7:30, Expert = 15:00
Solution: PDF
Note: Follow this link for other Snake puzzles. More Snake puzzles and variations can be found in Snake and Variations by Serkan Yürekli.
It took me a long while to spot the break-in because I kept misinterpreting the rules. It turned into a nice enjoyable solve once I realised my mistake.
12:27.Very nice and enjoyable solve.
I’m not sure what “how the snake passes through the shapes” means. Does it mean the same squares are visited by the snake, or do the directions from which the snake enters the shapes also count? Does the snake have to pass through the squares in the same order? It’s just too ambiguous.
Nounverber: The order of visited squares in a region does not matter. Only the set of visited squares must match for regions that exactly match shape. For example, a 2×2 region with only the top two squares visited by the snake entering on the left and leaving on the right (assume one dot of the two is the start of the snake) matches a 2×2 region with only the top two squares visited by the snake entering on the right and leaving on the left.