Red and blue design diagram

Quick answer：

A red and blue design diagram typically refers to a visual representation that uses red and blue colors as its primary elements. It could be used in various contexts such as art, architecture, or technology. In art, it might represent a color scheme or artistic composition. In architecture, it could be a plan or elevation showing the use of red and blue in a building design. In technology, it might refer to a circuit diagram or a UI design that incorporates these colors. The specifics would depend on the context in which the diagram is used.