  We extend our 2+1 dimensional discrete growth model (PRE 79, 021125 (2009))
with conserved, local exchange dynamics of octahedra, describing surface
diffusion. A roughening process was realized by uphill diffusion and curvature
dependence. By mapping the slopes onto particles two-dimensional,
nonequilibrium binary lattice model emerge, in which the (smoothing/roughening)
surface diffusion can be described by attracting or repelling motion of
oriented dimers. The binary representation allows simulations on very large
size and time scales. We provide numerical evidence for Mullins-Herring or
molecular beam epitaxy class scaling of the surface width. The competition of
inverse Mullins-Herring diffusion with a smoothing deposition, which
corresponds to a Kardar-Parisi-Zhang (KPZ) process generates different
patterns: dots or ripples. We analyze numerically the scaling and wavelength
growth behavior in these models. In particular we confirm by large size
simulations that the KPZ type of scaling is stable against the addition of this
surface diffusion, hence this is the asymptotic behavior of the
Kuramoto-Sivashinsky equation as conjectured by field theory in two dimensions,
but has been debated numerically. If very strong, normal surface diffusion is
added to a KPZ process we observe smooth surfaces with logarithmic growth,
which can describe the mean-field behavior of the strong-coupling KPZ class. We
show that ripple coarsening occurs if parallel surface currents are present,
otherwise logarithmic behavior emerges.
