How does the choice of a black-box style influence the model and implementation of a program using Solver? It's true that simply solving the problem, like a black box, is often the expressed goal of a new project. However, experience has repeatedly shown that user-acceptance is low for black-box applications, in large part because such an opaque model does not inspire user-confidence. Users cannot see what is going on and consequently doubt the solution from a black-box application.