As something given beyond what is really due, the Parthenon (designed by architects Iktinos and Kallikratis) became a masterpiece of architecture and art where some details of the features were realized. the temple perfectly balanced in shape and symmetry. Cartwright (2012) emphasized these details clearly in advance: "The temple measures 30.88 m by 69.5 m and was built using a 4:9 ratio of column diameter to l space between columns, the height of the building in relation to its width, and the width of the interior cella in relation to its length. Other sophisticated architectural techniques were used to combat the problem that anything at this size scale that was perfectly straight when viewed from a distance was curved. To give the illusion of the real thing, the columns tilt slightly inward, a feature that also gives a lifting effect to the building, making it appear lighter than its construction materials suggest. Additionally, the stylobate or floor of the temple is not exactly flat but rises slightly in the center. The columns also have an entasis, that is, a slight increase in the middle, and the four corner columns are imperceptibly faster than the others.