  The pattern transition induced by lattice anisotropy (LA) and magnetic
impurities is computationally observed in near-optimally doped d-wave
superconductors (DSCs). For the single impurity case, a transition from the
checkerboard to stripe pattern can be induced even with a very weak LA.
Moreover, the modulation period of eight lattice constants (8$a$) in the spin
order coincides with neutron scattering data. For the two-impurity case, an
orientation transition from the longitudinal impurity-pinned stripe into the
transverse pattern is observed when the LA ratio reaches some critical value.
At the critical point, it is found that the structures around magnetic
impurities could restore checkerboard patterns. These results indicate that the
formation of stripes in DSCs might induced by various effects, and could be
tunable experimentally.
