Fabrica et vsvs : instrvmenti ad horologiorvm descriptionem peropportvni : accessit ratio describendarvm horarum a meridie & media nocte exquisitissima, & nunquam ante hac in lucem edita
Fabrica et vsvs is a 1586 Latin treatise on sundial construction by the Jesuit mathematician Christoph Clavius, printed in Rome by Bartholomaeus Grassius for scholars and instrument makers. Its pages show geometric diagrams of hour lines radiating from a central point, with lettered points and construction lines drawn over the grid; a designer might take the radiating hour-line fan and the clean lettered diagram layout as a model for radial geometry.
