  The triangular lattice model with nearest-neighbor attraction and
third-neighbor repulsion, introduced in [J. Pekalski, A. Ciach and N. G.
Almarza, arXiv:1401.0801 [cond-mat.soft]] is studied by Monte Carlo simulation.
Introduction of appropriate order parameters allowed us to construct a phase
diagram, where different phases with patterns made of clusters, bubbles or
stripes are thermodynamically stable. We observe, in particular, two distinct
lamellar phases - the less ordered one with global orientational order and the
more ordered one with both orientational and translational order. Our results
concern spontaneous pattern formation on solid surfaces, fluid interfaces or
membranes that is driven by competing interactions between adsorbing particles
or molecules.
