https://docs.google.com/presentation/d/1GFfrATNtY6wRFBbIW_t7OT6dq2afv6Au/edit#slide=id.p1

https://docs.google.com/presentation/d/1K_iRNVJ2quFbtbQZ3qFOrJK4PuGXYNM-/edit#slide=id.p31