Bonus: Prime Snake by Serkan Yürekli
or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between a number entry mode and 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: Clue Symmetry and Logic
Author/Opus: This is the 95th puzzle from our contributing puzzlemaster Serkan Yürekli.
Rules: Fill in every circle inside and outside the grid with a prime number. (All prime numbers inside and outside the grid are marked.) Then locate a numbered snake (a 1-cell wide path) that starts with 1 and goes to 45 (1 to 11 in example). The snake cannot touch itself, not even diagonally. Digits outside the grid indicate how many cells in that row or column are occupied by the snake.
Answer String: Enter the length in cells of each of the snake segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma. The answer to the example is “3,11”.
Time Standards (highlight to view): Grandmaster = 3:45, Master = 5:30, Expert = 11:00
Solution: PDF
Note: Follow this link for other Snake puzzles.
Not difficult at all. I hardly need to give a hint, but should you absolutely need one, it’ll probably help for you to write down the numbers from 1 to 45 on a separate piece of paper and circle which ones are prime.
Seems like this puzzle type can only ever be a one-off, but it was a lot of fun.