OPTICAL PARADOX
A term introduced in or shortly before 1892 by the German philosopher and psychologist Franz Clemens Honoratus Hermann Brentano (18381917) to denote an "optical illusion such as the " Müller-Lyer illusion.
References
Brentano, F. (1892). Uber ein optisches Paradoxon.Zeitschrift fur Psychologie und Physiologie der Sinnesorgane, 3, 349-358.