Which in turn is based on the size of a equine derriere, as the story goes. https://www.precisioncontent.com/blog/on-rocket-ships-and-horses-behinds-where-did-

Which in turn is based on the size of a equine derriere, as the story goes. https://www.precisioncontent.com/blog/on-rocket-ships-and-horses-behinds-where-did-your-content-standards-come-from/ https://www.precisioncontent.com/blog/on-rocket-ships-and-ho...