The article explains how our eyes often mislead us, affecting design perception. It highlights that shapes like circles and squares of equal size can appear different due to visual weight. To achieve balance, designers should adjust sizes accordingly. The piece also discusses optical alignment, noting that elements may seem misaligned even when they are not, and suggests compensating for this to ensure visual harmony. Additionally, it covers optical corner rounding, emphasizing the need for smooth transitions between straight lines and curves. Overall, it's an insightful guide for creating visually balanced user interfaces.