Theme: Question Marks
Author/Opus: This is the 172nd puzzle from our contributing puzzlemaster Serkan Yürekli.
Rules: Standard Cross the Streams rules.
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 = 3:15, Master = 5:15, Expert = 10:30.