Gnosis, is a spaced repetition system for note taking & self
testing, where notes are taken in a Question/Answer/Explanation
format & reviewed in spaced intervals, determined by the success or
failure to recall a given answer for question.

Gnosis implements a highly customizable algorithm, inspired by SM-2.
Gnosis algorithm does not use user's subjective rating of a note to
determine the next review interval, but instead uses the user's
success or failure in recalling the answer of a note.