In this model, the size of the triangle represents a person's growth. A person starts with a small triangle but with all 5 levels of the triangle in place. Thus a person starts with physiological as well as self actualisation needs, the angle of the upright triangle changes for any individual and it defines what the relationship is between the 5 levels for that individual. Yet they are always shaped from large at the bottom and small at the top.
The 3rd dimension is introduced as time, this creates a time series of growing triangles, showing the growth of a person.