How were the pillars on the Parthenon Arranged so that they seem straight?

The pillars on the Parthenon were designed using a technique called entasis, which involves a subtle curvature that makes them appear straight to the human eye. This curvature compensates for optical illusions that can occur when viewing straight lines, making the columns seem more robust and aesthetically pleasing. Additionally, the columns are slightly tapered, and their spacing is carefully calibrated to enhance the overall visual effect, creating a harmonious and balanced appearance. These design elements collectively contribute to the illusion of perfection in the structure.