Geometric problems rarely arise in practice in the abstract form in which they are usually offered by problem books. In real life, in technology, in science, the geometric side of the problem is mostly obscured, obscured by extraneous elements, from which it must be isolated before starting to solve. Often, just one such exposure of the geometric basis of a real task is almost equivalent to its resolution, because it leads an intricate question to a clear mathematical scheme. But the ability to find its geometric basis in a specific problem, to translate a real question into the language of geometry, requires a special skill; and, of course, it cannot be acquired by exercise solely on the off-the-shelf schemes usually offered by problem-makers.