We consider situations where rays are reflected according to geometrical optics by a set of unknown obstacles. The aim is to recover information about the obstacles from the travelling-time data of the reflected rays using geometrical methods and observations of singularities. Suppose that. for a disjoint union of finitely many strictly convex smooth obstacles in the Euclidean plane. https://www.markymarkscott.com/product-category/color-complete-shampoo/