Geometry of Shadow: Three Spheres under a Luminous Semicircle
A ruled semicircular light source and three spheres, each with a hatched shadow cone
A large semicircular luminous body is set out with a full ruled construction of radii and chords spanning the width of the sheet. Beneath it three spheres are ranged across a baseline, each casting a shaded conical shadow toward lettered points. A boxed block of mirror-script prose sits at the upper left with more writing below, none transcribed in the bundle, so further untranscribed text is present.
On this page
Ruled semicircular light source
The luminous body is drawn as a large semicircle framed by a rectangle, with straight lines ruled from its arc to points across the figure. It establishes an extended source whose separate parts illuminate the bodies below from different angles.
Three spheres and their derived shadows
Three spheres stand side by side on the baseline, each with a tapering shaded cone drawn beneath it toward lettered points. The row compares how bodies at different positions under the same extended light throw shadows of differing shape and depth.
Radii and chords structuring the figure
The construction is built from ruled radii, chords and crossing lines that fix the points where rays from the arc meet the bodies and the ground. The geometry underlies the whole demonstration of how the shadows are derived.