Yin has water and tree and Yang has fire and soil...metal is found between both of them. Below is how I will show each metal within the parklet.
Fire- will be light..since it will be open the sun itself will be the light
Soil- will be the ground itself
Tree- will use wood throughout the parklet, rectangular outline/furniture/benches, paper book covers which are found in the tables inside the book store so this will help tie the book store with the parklet in a way but still allowing it to look open to the public
Water- blue colored benches
Metal- railing/wires ( the metal will be the one to tie downtown with the parklet....you find metal structure throughout downtown so the parklet will have metal as well making it part of downtown)