To the untrained eye Greek temples appear deceptively simple in design and all seem to look alike. The apparent resemblance results from the similar design process used, which constituted the use of proportional developments on the site of construction after having laid out the full dimensions, so that most architects followed an established procedure.
However, the Parthenon is far from being just another temple following a basic plan, and its sheer colossal dimensions meant that it was unequalled in challenging the limitations of this technique.
The Parthenon adheres to an X to 2X plus 1 system that is found with the common ground plan of hexastyle by 13, but unusually for a temple of its scale it is octastyle by 17. More notably, however, a constant use of the proportion 4:9 can be found throughout the building. For example, the width of the stylobate relative to its length, the height of the columnar order up to the horizontal cornice relative to the temple's width, the diameter of the columns relative to the interaxial distance between the columns, and the width of the cella to its length are only some parts of the building which yield this 4 to 9 ratio. Consequently the Parthenon has a mathematical perfection which communicates itself as a coherent and harmonic whole that does not merit the label of a "box with a lid on it".
Perhaps more importantly the Parthenon is original and deviates from the norm insofar as it combines elements of both the Doric and Ionic architectural orders. Although it is technically Doric by order, and the bulk of its columns are Doric in style, the Parthenon incorporates elements of the elegant Ionic order. 4 Ionic columns supported the roof of the opisthodomos, the smaller rear room found behind the naos whilst a continuous frieze, a feature indicative of the Ionic order ran around the outside of the cella, within the colonnade. Ionic moulding to the architrave above the triglyphs and metopes can also be noted.