"One castaway would stand at the top of a tower and pour water down five gutters held by five castaways. The water would fill a barrel, which would release a net of puzzle pieces when full. The four remaining castaways would assemble the puzzle. The first tribe to assemble their puzzle would win." ~ @SurvivorWiki
They use the Medallion and give it to the other tribe.
The advantage is starting the challenge with one bucket already in the barrel.
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Proceed to tribe events.