sequential clyde notes, underneath similar mythologies:

past destructive event on earth

survivors, based on similar knowledge, are from a similar if not same culture or group

(possibly gathered together at a safe location prior to destruction)

they split up and travel to previously known world population centers

they help the people recover

they give them a condensed template of wisdom and knowledge of its use

(maybe geometry, from which natural expressions can be derived)

their benefactors either left to assist others or

died with the last group assisted.

once the benefactor dies,

what was given adapted itself the population over time

there are gains in use and application of the knowledge and wisdom

but was not sustained and its use gradually falls away.

before it could be lost,

it and its history is recorded in stories for future generations to use.

the cultures of the world that developed more quickly,

their stories developed as well, in depth, breadth & complexity,

as the environment allowed.

those that were slower or failed,

their stories remained in varying degrees of lesser development.

eventually these stories become rituals, prayers and religions.

leading to the use of the knowledge and wisdom by future generations.

a gestalt of sorts.