The Double-Heart of Stacked Stones is Cimei's signature sight: two linked heart-shaped fish traps built from piled basalt and coral in the intertidal zone. It is pretty, but it is not just decoration. Stone weirs are old Penghu fishing technology, designed to let fish swim in with the tide and trap them as the water falls.
Come at low tide, when the shape is visible. At high tide you may only see hints of the walls, and the famous view loses most of its point.