Ancient Greek architects were on to something when they built the Parthenon with subtle curves and no right angles. While it remains debatable, some scholars argue that these features were intended to counter the brain’s tendency to see optical illusions. www.pbs.org Watch "Secrets of the Parthenon" Tuesday, January 29 at 8pm ET/PT on PBS (check local listings). Or join us online at www.pbs.org "Secrets of the Parthenon" is a Providence Pictures production for NOVA and WGBH Boston in association with Studio International and ARTE France. Funding for NOVA is provided by David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, and public television viewers. Additional funding for "Secrets of the Parthenon" is provided by The Solow Art and Architecture Foundation. To learn more, visit www.pbs.org