Maslow described human needs as ordered in a prepotent hierarchy—a pressing need would need to be mostly satisfied before someone would give their attention to the next highest need. None of his published works included a visual representation of the hierarchy. The pyramidal diagram illustrating the Maslow needs hierarchy may have been created by a psychology textbook publisher as an illustrative device. This now iconic pyramid frequently depicts the spectrum of human needs, both physical and psychological, as accompaniment to articles describing Maslow's needs theory and may give the impression that the Hierarchy of Needs is a fixed and rigid sequence of progression. Yet, starting with the first publication of his theory in 1943, Maslow described human needs as being relatively fluid—with many needs being present in a person simultaneously.