Proportions

These drawings show the proportions of the different elements of the crane. This medieval technique is based on Euclidean geometry and uses simple ratios to determine the sizes and relationships of all of the parts. It allowed mediaeval builders to draw the design on paper without complicated drawing tools and reproduce the design at the work site without having to use giant versions of those complicated drawing tools. The same techniques were used to build everything from cathedrals to castles. This image is from http://www.roofs.cz