Is the cube spinning left or right? Looking down or up?
Necker Cube
Watch the spinning wireframe. Does it look like it's tilting down? Blink, and it might flip to tilting up.
Multistable Perception
🧊 Which side is front?▼
The **Necker Cube** is a wireframe drawing with no depth cues (like shading or occlusion). Mathematically, the image on your retina is compatible with two valid 3D interpretations: the lower-left face is in front, OR the upper-right face is in front.
Your brain cannot decide, so it switches back and forth between these two **bistable states**.