The vertical-horizontal illusion; an experimental study of meridional disparities in the visual field
A 1917 psychology monograph by Sarah Margaret Ritter, published in Princeton and Lancaster by the Psychological Review Company, reporting experiments on the vertical-horizontal illusion and how perception differs across meridians of the visual field. Its pictures are plain line diagrams: overlaid polygons and dashed outlines, radiating axis lines labelled in degrees, and a quarter-circle scale chart with stepped marks. A designer might draw on their clean technical linework, angular rosette geometry, and the way repeated outlines show distortion.
