Which Way It Faces
A wire cube that cannot make up its mind which of its faces is at the front.
Celle-ci n’est pas encore traduite : ses textes sont en anglais.
Comment jouer
Regardez d’abord, répondez ensuite
A wire cube that cannot make up its mind which of its faces is at the front.
- Moins d’une minute · une question · puis l’explication
Comment ça marche — à lire plutôt après avoir essayé
Two cubes in one drawing
Twelve lines fit two different cubes equally well, one seen from above with the lower-left face in front, one seen from below with the upper-right face in front. With nothing to choose between them, perception settles on one, tires of it, and flips to the other.
The Swiss crystallographer Louis Albert Necker noticed the flip in 1832 while drawing crystals. You can steer it a little: look at one corner and imagine it nearer, and the cube tends to rearrange itself around that choice.