https://docs.google.com/document/d/1twwQHWjC5x8AnJYfXal2iaZf-Hy9uHQQUGebl5wI1MA/edit?usp=drive_link
rewrite: https://docs.google.com/document/d/1qfPYRTxah9LWYyPggUhCK6rCg34zBnlea9xV6ETReac/edit?usp=sharing