In this chapter, we looked at effective techniques designers use to harmonize surfaces, spaces, objects, sounds, and motion to support engagement, interaction, and delight--the outcomes most companies and designers aspire to have in their products.

Blending the various ingredients that make up an engaging, positive experience is complex, because multiple independent variables must integrate consistently and predictably at the right moment to deliver the desired outcome. Many of the techniques explored here have been acquired over centuries of continuous tweaking and evolution of products and design.

Delight is joyful satisfaction that results from continuous, consistent engagement with a product. It is a reproducible emotional state, an experience that does not wear off easily despite frequent use. Engagement and delight depend on functional execution of the product. It is critical that the product not only looks good and feels good but it must be good.

In the next chapter, we look at concept development and design, the phases during which designers assemble everything they know about the product's target audience, users, the company's competitive objectives, business and technical requirements, and come up with a unified design framework that ties together all the elements necessary for guiding the creation of the final product.