From Wikipedia: In manufacturing and design, a mockup, or mock-up, is a scale or full-size model of a design or device, used for teaching, demonstration, design evaluation, promotion, and other purposes. A mockup is a prototype if it provides at least part of the functionality of a system and enables testing of a design. Mock-ups are used by designers mainly to acquire feedback from users. Mock-ups address the idea captured in a popular engineering one-liner: You can fix it now on the drafting board with an eraser or you can fix it later on the construction site with a sledge hammer.
From Wikipedia: Responsive web design (often abbreviated to RWD) is a web design approach aimed at crafting sites to provide an optimal viewing experience—easy reading and navigation with a minimum of resizing, panning, and scrolling—across a wide range of devices (from desktop computer monitors to mobile phones).
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