Typeface Mechanics: 001 

Square and round shapes: mathematically equal, or optically equal
Square and round shapes: mathematically equal, or optically equal

By the time I really started paying attention to fonts about a year ago, Tobias Frere-Jones had already split from Jonathan Hoefler.

If you care about design, this is a great read, and Frere-Jones’ is a great blog to follow.

(From Daring Fireball)