Avoid adding to complex idea using the same medium. A visual idea should be narrated via audio, NOT added to visually.
"explanatory information has less impact on working memory if it is narrated, rather than added to an already complex diagram."
As working memory is finite, we want to conserve it as a resource. Therefore we should seek to change mediums when revisiting older information.
This may work as a sort of Progressive Summarization based around transposition between mediums.