change in sign and they produce a nonzero skewness in the horizontal divergence, similar to the supergranular divergence maps (see Section \[secDataIntro\])[[;]{}]{} see the skewness of each pattern given in Figure \[figPatterns\].

The case $A=-1$ corresponds to a pattern of inverted hexagons (see right panel in the bottom row of Figure \[figPatterns\]). This corresponds to downflows surrounded by a network of upflows as considered by @Busse2004 [@Busse2007].

The case $A=0$ corresponds to rectangles, and we can vary $A$ continuously between zero and one to obtain patterns with different coupling amplitudes, intermediate between rectangles and hexagons; see the example labeled “small coupling” ($A=0.3$) in Figure \[figPatterns\].

In addition to these patterns, it is possible to tessellate space by a pattern generated from any combination of three wave vectors with $\bk_0+\bl_0=\bmm_0$, each with a separate, possibly complex Fourier amplitude. For a given pattern, the phases of $X(\bk_0)$ and $X(\bl_0)$ may be jointly put to zero by a translation in real space. Statistically, we do not expect any preferred direction for supergranular divergence maps near the equator, and it is therefore reasonable to assume $|X(\bk_0)|=|X(\bl_0)|$ for illustrative purposes. [[The Fourier amplitudes of $X$]{}]{} may [then]{} be normalized to one as done above.

For 