This is a “Twisted Tuesday” puzzle variation.
Theme: Totally symmetric?
Rules: Standard Masyu rules. Also, all possible white and black circles have been given. (In other words, the loop cannot turn in any unlabeled spot and then continue straight in the next two cells as that should be a black circle; the loop also cannot go straight in any unlabeled spot and then turn in one of the adjoining cells as that should be a white circle.)
Answer String: Enter the length in cells of the horizontal loop segments from left to right in the marked rows, starting at the top. If the loop only has vertical segments in the marked row, enter 0. Separate each row’s entry with a comma.
Time Standards (highlight to view): Grandmaster = 2:30, Master = 4:00, Expert = 8:00