  It is proposed, that a two-dimensional magnetic superstructure closely
related to the one mentioned recently by Christensen et al. [cond-mat/0608204]
constitutes a viable interpretation of the four-fold splitting of the magnetic
(\pi, \pi) peak in lanthanum cuprates. (This splitting is usually interpreted
as the evidence for stripes.) The superstructure in question has the topology
of the square crystal of magnetic vortices with approximate periodicity (4a x
4a). This vortex crystal exhibits no magnetic antiphase lines. It is shown that
such a superstructure is magnetically stable in the approximation of staggered
spin polarizations, and that it should be accompanied by charge modulation
characterized by charge peaks at the positions observed experimentally.
