Tetris puzzle in the marsh with no use?
Solution 1:
Without getting in a discussion about purpose of playing the game in the first place... Well, you have +1 solved puzzle for every solved puzzle!
As far as my experience goes, a lot of end-game puzzles are only there to be there, as an additional challenge. This puzzle including: I have not seen any events after solving it.
Even more: AFAIK the game has very direct feedback when something happens: line turns on, there is sound (with a pause after sound for completing the puzzle), etc. Nothing here, so this puzzle is a dead end.