SCATTERING FROM A SQUARE OBSTACLE

We use the scattering from a square obstacle as an example to illustra te the method of quantization of billiards from a scattering point of view. At the same time, we discuss rather surprising quantum and class ical aspects of this simple scattering system. We attribute these pecu liarities to the fact that the square presents to the outside obtuse a ngles at the corners. These properties are typical of the class of ''q uasi-integrable'' scatterers.