https://docs.google.com/document/d/17kVPogMyPTDOgWB4bKQ1eX15Q1ZoXBitDxazyG4-6bw/edit?usp=sharing
https://docs.google.com/document/d/1PiY8nxUYXVBemTmEXEfemkdzmLbjELZMdwmVnyLdcCA/edit?usp=sharing