  We investigate the assembly of the dipole-like patchy particles confined to a
spherical surface by Brownian dynamics simulations. The surface property of the
spherical particle is described by the spherical harmonic $Y_{10}$, and the
orientation of the particle is defined as the uniaxial axis. On a flat space,
we observe a defect-free square lattice with nematic order. On a spherical
surface, defects appear due to the topological constraint. As for the director
field, four defects of winding number $+1/2$ are observed, satisfying the Euler
characteristic. We have found many configurations of the four defects lying
near a great circle. Regarding the positional order for the square lattice,
eight grain boundary scars proliferate linearly with the sphere size. The
positions and orientations of the eight grain boundary scars are strongly
related to the four $+1/2$ defect cores.
