Art with a deeper meaning

An optical illusion is not just an art form that is meant to mislead; it’s also an art form with a deeper, sometimes personal meaning, like this example by Willem Bilderdijk.

Take a look at his other optical illusions as well. Can you guess the hidden meaning? Used literature: T. Geerts, Het Bilderdijk-Museum. Catalogus van kunstvoorwerpen. Leiden 1994, nr. 101 en J. Bosch, "The artistry of Willem Bilderdijk's emblematic engravings". In: J. Lachlan Mackenzie and Richard Todd (red.), In Other Words. Transcultural Studies in Philology, Translation and Lexicology. Presented to Hans Meier on the Occasion of his 65th Birthday. Berlijn/Boston 1989, pp. 133-144.