  A method to visualize polytopes in a four dimensional euclidian space
$(x,y,z,w)$ is proposed. A polytope is sliced by multiple hyperplanes that are
parallel each other and separated by uniform intervals. Since the hyperplanes
are perpendicular to the $w$ axis, the resulting multiple slices appear in the
three-dimensional $(x,y,z)$ space and they are shown by the standard computer
graphics. The polytope is rotated extrinsically in the four dimensional space
by means of a simple input method based on keyboard typings. The multiple
slices are placed on a parabola curve in the three-dimensional world
coordinates. The slices in a view window form an oval appearance. Both the
simple and the double rotations in the four dimensional space are applied to
the polytope. All slices synchronously change their shapes when a rotation is
applied to the polytope. The compact display in the oval of many slices with
the help of quick rotations facilitate a grasp of the four dimensional
configuration of the polytope.
