  We theoretically predict and experimentally verify the illusion of
transforming the magnetic signature of a 3D object into that of another
arbitrary object. This is done by employing negative-permeability materials,
which we demonstrate that can be emulated by tailored sets of currents. The
experimental transformation of the magnetic response of a ferromagnet into that
of its antagonistic material, a superconductor, is presented to confirm the
theory. The emulation of negative-permeability materials by currents provides a
new pathway for designing devices for controlling magnetic fields in
unprecedented ways.
