Impossible cube

The Impossible crate is an impossible figure, ie a three-dimensional optical illusion, based on the experience in spatial vision and knowledge of geometric bodies and perspective laws.

The Riddle

The box is the viewer at a distance exactly as presented, as shown in Figure 1. An increase of the effect can be achieved, that the performer is in the box by it. The viewer thinks now see a box that forms from twelve battens, the edges of a cube, but it can not exist.

Experience tells the viewer that both the top front crossbar as well as the vertical bar in the left foreground ( in the second illustration green) must be visually in front of the other slats due to the laws of perspective. Nevertheless, the viewer sees supposedly that the vertical bar right behind the transverse bottom rear (red) superimposed on these two, which is impossible.

The solution

The illusion based on the fact that the box is not that's what they seem to be. If you tilt the box slightly, it can be seen that it does not consist of twelve continuous slats. As illustrated in Figure 3, gaps have been cut so skillfully that you can see the trailing slats at the screening through these gaps in two of the slats.

The illusion is only possible with a certain distance to the viewer and only if this does not move much. Spatial vision is based on the balance of the two individual images of the right and of the left eye; these frames are, however, with increasing distance of the observed object, so that the depth or distance of an object is always like getting worse estimate. When the viewer moves, he can estimate from the relative position of objects whose actual situation: According to experience, move distant objects in the visual field less than more.

With sufficient distance and relative immobility, such as by a fixed camera, the viewer will be taken of these opportunities and his vision practically reduced to two dimensions, so it is dependent on other benchmarks. Without information to the depth is ultimately to see only a two-dimensional projection, which is extrapolated on the basis of experience with such projections (such as illustrations in books, but also television pictures ) back to the third dimension. The image of a cuboid is so familiar that something that is only sufficiently similar - as the "impossible crate " - is involuntarily reduced to the familiar form, even if the mind tells you that this is physically impossible.

The most impressive effect of such "impossible body " like the crate based on the fact that there are actual body and not merely to their images, but explicitly in terms of the two-dimensional projection ( and deception ) that give rise to, were constructed. Due to the physicality is the seen attached greater credibility than would be the case with a bare area display.

Origin and use

Author of this and other "impossible body " is the British psychologist Richard Gregory, who deals with sensory perceptions and deceptions.

The "impossible crate " served the Dutch graphic artist MC Escher as a model for his lithograph " Belvedere ".