Visual illusions, their causes, characteristics and applications (1922)
Luckiesh, Matthew, b. 1883 · New York, D. Van Nostrand company · leaf 205
190 VISUAL ILLUSIONS be exhibited in a booth — a huge shadow-box not unlike a show-window in which the light-sources are concealed. Such experiments yield many interesting data pertaining to the illusions which the painter strives to obtain. Incidentally on viewing some picture frames in which the… … Fig. 82. — Illustrating the apparent distortion of a picture frame in which the grain of the wood is visible. did not appear to be strictly rectangular. The illusions were so strong that only by measuring the frames could one be convinced that they were truly rect- angular and possessed straight…
Optical illusions
Internet Archive · Cornell University Library · Public domain (published before 1931). Free to use for anything.
![An illustration from Heydenweldt Vnd [und] irer Götter anfängcklicher vrsprung [Ursprung]: durch was verwhänungen den selben etwas vermeynter macht zugemessen, vmb dero wille[n], sie von den alten verehert worden ... (1554)](https://img.insideoutlibrary.com/img/200/heidelberg-herold1554-468-2.webp)
