Substitutions with Vanishing Rotationally Invariant First Cohomology

<table>Vertex configurations in <svg height="11.6125" id="M271" style="vertical-align:-0.0pt" version="1.1" viewbox="0 0 11.45 11.6125" width="11.45" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,0,0,-.017,.062,11.55)"><path d="M649 676l-22 -187l-33 -2q3 56 -12 94q-8 20 -31.5 26.5t-86.5 6.5h-74l-90 -491q-4 -23 -6 -36.5t1 -25t7 -16.5t18 -9t27 -5t41 -3l-6 -28h-286l4 28q68 5 84 18.5t28 76.5l94 491h-55q-74 0 -100.5 -6t-41.5 -23q-24 -29 -54 -98l-32 1q32 98 53 188h22q7 -18 15 -22
t37 -4h417q23 0 33.5 5t25.5 21h23z" id="x1D447"></path></g>
</svg>.</table>

Discrete Dynamics in Nature and Society

fig8

Figure 8

Figure 8: Substitutions with Vanishing Rotationally Invariant First Cohomology 