 Genaille–Lucas rulers

Genaille–Lucas rulers are specialized measuring devices designed to facilitate the quick and accurate division of a line segment into fractional parts. They are named after the mathematicians who developed the concept, specifically the French mathematicians Jules Genaille and Émile Lucas. The rulers are based on a unique geometric construction that allows for easy measurement of rational lengths, making them useful in various applications, particularly in fields such as architecture, engineering, and drafting.