The "Mountain Or Valley?" Illusion

The video explores multi-stable perceptual illusions, focusing on how light and shadows affect our perception of 3D features. It explains why we perceive certain features as convex or concave based on shadow placement, influenced by cultural and artistic conventions. The video also discusses how these illusions apply to geographic features, such as mountains and valleys, and how cartographers use lighting conventions to accurately depict them on maps. The video concludes with a practical tip for viewing maps to avoid misperceptions.

What is the significance of light direction in the interpretation of shaded relief maps?

Describe the experience the speaker had when viewing a map upside down and its implications on perception.