Left: illustration and text from De Divina Proportione, by Luca Pacioli, an early work
of 3 separate volumes. First a volume about the golden ratio, polygons, and perspective. Then one about the ideas of Vitruvius on math in architecture. Then one that’s mainly an Italian translation of Piero della Francesca’s Latin writings on polyhedra.
Right: head wired for electroencephalogram.
(Left image from Tidbits of Geometry, right image via ffffound.)