Which of the following is NOT a product design method?

Design for aesthetics is primarily focused on the visual appeal and sensory perceptions of a product, rather than being a method for designing products in a structured, iterative manner. User-centered design, co-design, and design for manufacture are all systematic approaches used in product design processes.

User-centered design emphasizes understanding the needs, preferences, and limitations of the end-users, while co-design actively involves stakeholders in the design process, ensuring diverse perspectives are incorporated. Design for manufacture is a method that focuses on both the ease of manufacturing and the cost-effectiveness of production. In contrast, focusing solely on aesthetics does not constitute a design method aimed at holistically developing a product with consideration for functionality, user interaction, or manufacturability. Thus, design for aesthetics stands apart as it is more about the outcome rather than a methodical approach to product design.