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Theme: 25 years from 1991/03/02 to 2016/03/02
Author/Opus: This is the 115th puzzle from our contributing puzzlemaster Prasanna Seshadri.
Rules: This puzzle is a variation of Castle Wall.
Standard Castle Wall rules:
Draw a single closed loop (without intersections or crossings) passing through some empty cells in the grid. The grid contains some bordered or colored cells that cannot be part of the loop. Black cells must be outside the loop; white cells (with heavy borders) must be inside the loop. Numbers and arrows refer to the total sum of the lengths of loop segments in the given direction. (An equivalent way to understand these values is to count the number of cell borders crossed by the loop in that direction.)
+ Towers Variation:
Also, the numbers outside the grid show the number of empty cell segments visible in that direction (ignore all clue cells and all cells used by the loop). A segment of length N in a given direction is taken as a building of height N. Buildings of height N block the view of all buildings behind them of equal or lesser height.
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. This example has the key “2,21”.
Time Standards (highlight to view): Grandmaster = 30:00, Master = 1:00:00, Expert = 2:00:00
Note: You can find other Castle Walls here.