Observing other universe through ringholes and Klein-bottle holes
  It is argued that whereas the Shatskiy single rings produced by the
gravitational inner field of a spherically symmetric wormhole and the
concentric double Einstein rings generated by a toroidal ringhole could not be
used without some uncertainty to identify the presence of such tunnelings in
the universe or the existence of a parallel universe, the image which the inner
gravitational field of a non orientable Klein-bottle hole tunneling would leave
by lensing a single luminous source is that of a truncated double spiral, which
is a signature that cannot be attributed to any other single or composite
astronomical object in whichever universe it may be placed. In this report we
argue some more reasons to predict that such a signature would imply the
discovery of one such non orientable tunneling in our or other universe. After
all, a nonorientable Klein-bottle hole is also a perfectly valid solution to
the Einstein equations and the stuff which would make it feasible is becoming
more and more familiar in cosmology.
