The metaphor of this article is as follows:

1. Hamburg is like a gourmet castle, with two pieces of bread as a solid wall, crispy patties as the main building of the castle, and vegetables and sauces as exquisite decorations.

2. Hamburgers are like a gift from nature. Two pieces of bread represent heaven and earth, patties are the earth, and vegetables and sauces are rainbows and rain.

3. Hamburg is like a food symphony, with two pieces of bread as a stable movement, patties as an impassioned melody, and vegetables and sauces as a harmonious soundtrack.