To invisibly embed additional information in a base pattern and to
visualize the additional information, a dislocation is provided in a
boundary between the base pattern compose of striped thin lines and the
additional information pattern composed of striped thin lines. This
dislocation makes the stripes of the patterns discontinuous. The
additional information pattern is invisibly embedded in the base pattern
such that a sequence of dislocations in the stripes forming the boundary
is at an angle equal to or larger than a predetermined angle with respect
to the stripe direction.
