its front, the temple is a pure , its external walls align with the axes of the second and seventh columns. In other regards, the Parthenon is distinguished as an exceptional example among the mass of Greek by many distinctive aesthetic solutions in detail. For example, the of and are shortened so as to form simple pillars. Instead of longer , there are prostyle colonnades inside the on the front and back, reflecting Ionic habits. The execution of the , with a western room containing four columns, is also exceptional. The Parthenon's Archaic predecessor already contained such a room. All measurements in the Parthenon are determined by the proportion 4:9. It determines column width to column distance, width to length of the stylobate, and of the without . The temple's width to height up to the is determined by the reverse proportion 9:4, the same proportion squared, 81:16, determines temple length to height. All of this mathematical rigour is relaxed and loosened by the optical refinements mentioned above, which affect the whole building, from layer to layer, and element to element. 92 sculpted metopes decorate its triglyph frieze: centauromachy, amazonomachy and gigantomachy are its themes. The external walls of the are crowned with a figural frieze surrounding the entire and depicting the Panathenaic procession as well as the Assembly of the Gods. Large format figures decorate the pediments on the narrow sides. This conjunction of strict principles and elaborate refinements makes the Parthenon the paradigmatic Classical temple. The Temple of Hephaistos at Athens, erected shortly after the Parthenon, uses the same aesthetic and proportional principles, without adhering as closely to the 4:9 proportion. Late Classical and Hellenistic: changing proportions In the 4th century BCE, a few Doric temples were erected with 6 × 15 or 6 × 14 columns, probably referring to local Archaic predecessors, e.g. the Temple of Zeus in Nemea and that of Athena in Tegea. Generally, Doric temples followed a tendency to become lighter in their superstructures. Columns became narrower, intercolumniations wider. This shows a growing adjustment to the proportion and weight of Ionic temples, mirrored by a progressive tendency among Ionic temples to become somewhat heavier. In the light of this mutual influence it is not surprising that in the late 4th century BCE temple of Zeus at Nemea, the front is emphasised by a two intercolumniations deep, while the is suppressed. Frontality is a key