History 4, Lesson #89: https://essaybank.home.blog/2020/02/21/history-lesson-90-the-heliocentric-theory-vesalius-%e2%9c%8f%ef%b8%8fand-the-pencil-%e2%9c%8f%ef%b8%8f/
History 5, Lesson #11: https://essaybank.home.blog/2020/09/14/history-lesson-15-2/
These two essays that include the pencil are a two-part story.