To counteract the apparent distortions of perspective in the parthenon, the architects who designed it actually created a( a0 illusion.

They created an Optical Illusion.

The way we see object in a specific area differs significantly depending on our distance and point of view when we see it.

To counteract it ( for example if they want the building to look nice in the picture), many architects create an optical Illusion and it will negate the effect of the distorsion