OpenGL is a graphics library used for 2D and 3D visualization that allows developers to configure a graphics pipeline and submit data to it. OpenGL for Embedded Systems (OpenGL ES) is a simplified version for mobile systems. OpenGL is useful for mobile because it utilizes the GPU's hardware acceleration, improving performance for graphics operations that have a parallel structure like effects, textures, and lighting. Some examples of mobile apps that use OpenGL for their user interfaces include Instagram for filters, Netflix for its UI, and iBooks and Flipboard for their page turning animations.