Sources
Where the facts come from
Every fact on this site was checked against these pages on 14 November 2026. We quote the article body, not captions we cannot see, and we do not use Wikipedia.
- Encyclopaedia Britannica Scholars: illusion, checked 14 November 2026
- Encyclopaedia Britannica Students: illusion, checked 14 November 2026
- Encyclopaedia Britannica Scholars: perception, checked 14 November 2026
- OpenStax, Psychology 2e, section 5.6 Gestalt Principles of Perception, checked 14 November 2026
- Michael Bach: Necker Cube, checked 14 November 2026
- Michael Bach: Rotating face mask (hollow face), checked 14 November 2026
- Michael Bach: Optical Illusions / Visual Phenomena (index), checked 14 November 2026
- Jörgen L. Pind, “Looking back: Figure and ground at 100”, The Psychologist (British Psychological Society), 13 January 2012, checked 14 November 2026
- The Illusions Index: Rubin’s Vase, checked 14 November 2026
Drawings are our own, simplified and not to scale. This site is independent and is not affiliated with, or endorsed by, Encyclopaedia Britannica, OpenStax, Michael Bach or the British Psychological Society.