https://docs.google.com/presentation/d/1XrQEratuDd5z7UOqZFYIS0LKdKBMMrol15_TAH01YXg/edit#slide=id.p
https://docs.google.com/presentation/d/119WXBfewv4LT0-D1K7mPDOu486ZF314mjs_1m1N9jWo/edit?usp=sharing