Engineering: large cogs meshing together, and diagrams of epicycloid curves. Colour lithograph by Stanislas Petit, ca. 1905. https://www.rawpixel.com/image/13951560/image-background-paper-cartoonFree Image from public domain licenseEngineering: large cogs meshing together, and diagrams of epicycloid curves. Coloured lithograph, 1905, by Stanislas Petit. https://www.rawpixel.com/image/13968889/image-paper-art-patternFree Image from public domain license