Overview
This is a simple guide for the Ginger Island Mermaid Puzzle Key: Must be raining. Step 1: Go to the far right beach and have 5 Flute Blocks Step 2: Pitch them so that they match the mermaid song from the Winter Market (2 clicks for the first block, 11 clicks for the second, 9 clicks for the third, 5 clicks for the fourth, 7 clicks for the fifth) If you get it right, the mermaid smiles on the rock and waves at you. You get 5 golden walnuts.
The Gist of Things
Literally just check description for the quick guide.