Verso Spherical geometric design

This drawing features a precise construction of a sphere, mapped with radiating lines and intersecting arcs in brown ink or metalpoint. The diagram serves as an exercise in solid geometry and perspective, showing how to plot points on a curved surface. Faint inventory numbers and a signature are visible at the bottom of the sheet, indicating its history as a collected object.

This study reflects the Renaissance integration of mathematics and art, where geometry was seen as the underlying blueprint of the natural world. It connects to the Neoplatonic belief that mathematical laws govern the cosmos, a theme central to Raphael's 'The School of Athens' where such geometric principles are celebrated as the peak of human reason.