English: An anamorphosis is a deformed image that appears in its true shape when viewed in some "unconventional" way. According to Webster's 1913 Dictionary:

A distorted or monstrous projection or representation of an image on a plane or curved surface, which, when viewed from a certain point, or as reflected from a curved mirror or through a polyhedron, appears regular and in proportion; a deformation of an image. In one common form of anamorphosis---usually termed "oblique"--- the unconventionality arises from the fact that the image must be viewed from a position that is very far from the usual in-front and straight-ahead position from which we normally expect images to be looked at.

In a common form---sometimes termed "catoptric"---the image must be seen reflected in a distorting mirror (typical shapes being cylindrical, conical and pyramidal).

English: reflection of a carpet into a cylindrical bin