The basic proportions of the building were determined by the numeric relationship of columns on the front and back to those on the sides. The classic solution chosen by Greek architects is the formula frontal columns : side columns = n : (2n+1), which can also be used for the number of intercolumniations. As a result, numerous temples of the Classical period in Greece (c. 500 BCE to 336 BCE) had 6 × 13 columns or 5 × 11 intercolumnitions. The same proportions, in a more abstract form, determine most of the Parthenon, not only in its 8 × 17 column peristasis, but also, reduced to 4:9, in all other basic measurements, including the intercolumniations, the stylobate, the width-height proportion of the entire building, and the geison (here reversed to 9:4).