They show the spread of the cult of Apollo and the evolution of Greek architecture, which was mostly based on the rightness of form and on mathematical relations.
ðeɪ ʃˈoʊ ðə spɹˈɛd ʌvðə kˈʌlt ʌv ɐpˈɑːloʊ ænd ðɪ ˌɛvəlˈuːʃən ʌv ɡɹˈiːk ˈɑːɹkɪtˌɛktʃɚ, wˌɪtʃ wʌz mˈoʊstli bˈeɪst ɔnðə ɹˈaɪtnəs ʌv fˈɔːɹm ænd ˌɔn mˌæθɪmˈæɾɪkəl ɹᵻlˈeɪʃənz.