sentences:  Whereas other game engines would have to modify the shape of the altered object to create a similar effect, Re-flex creates special objects which represent empty space.When, for example, an explosion blows a hole in a rock wall, the Re-flex technology creates an "empty space" object which is the approximate size and shape of the explosion.The use of a specially designed test level in the beta version shown at E3, and the decision to release it exclusively for the Dreamcast, was chiefly to demonstrate the unlimited possibilities that the Re-Flex geography system was capable of; which was once thought impossible to do on a home console.