Pestalozzi's Idee eines ABC der Anschauung als ein Cyklus von Vorübungen im Auffassen der Gestalten
A German pedagogical treatise by Johann Friedrich Herbart, published in 1804 and drawn from Heidelberg University Library, written as a set of preliminary exercises for teaching children to perceive shapes after Pestalozzi. The single picture shows two plane-geometry diagrams in a fine-lined engraved style: a quarter circle divided into radiating sectors over a square grid labelled Fig. 2, and a triangle with a perpendicular and angle marks labelled Fig. 3. A designer might take from it the clean, instructional look of early diagrams, with labelled figures and measured construction lines.
