Nomograms are graphical representations of logical relationships that are defined by mathematical formulae. They visualise the complex interplay of several parameters in the form of an abstract drawing and thus turn it into a symbolic sign. Nomography "draws" in its Greek-Latin meaning "the word (or law)." It goes back to the ideas of a Swiss railway construction director, Léon Lalanne (1811-1892), on the one hand and to the work of French engineers Philbert Maurice d'Ocagne and Rodolphe Soreau from the early 20th century on the other.Nomograms are also known as 'alignment charts' in contrast to grid charts or diagrams: In the diagram, three lines that intersect at one point provide the result, whereas, in the nomogram, they lie on a straight line that connects three points. Nomograms can also be mechanised, for example as so-called sliding leaf nomograms (like a slide rule). It is possible that there were already pre-forms of nomograms in antiquity and before the beginning of our era. For example, the 'Nebra Sky Disc' can also be interpreted as a nomogram.With the spread of electronic calculating machines and later computers, nomography became increasingly forgotten. Today, results are achieved by entering data into a computer programme that represents mere numerical values as semiotically reduced information.The presentation is devoted to tracing the causes of the banalisation of the knowledge process and understanding and the obscurity of understanding a complex context.