% Qualitative report-plane schematic only; radii and phases are not data.
% Inner phases: cube roots of unity. Outer phases: two conjugate pairs with
% cosines x=3/5 and y=-5/6 (xy=-1/2), an illustrative member of the
% construction of eq:sevenphases; the actual x,y follow from the certified branch.
\begin{tikzpicture}[font=\small,>=stealth,line cap=round]
 \definecolor{innerblue}{HTML}{0072B2}
 \definecolor{outerorange}{HTML}{D55E00}
 \draw[->,gray] (-2.15,0) -- (2.3,0) node[right,black] {\(a_1\)};
 \draw[->,gray] (0,-2.1) -- (0,2.15) node[above,black] {\(a_2\)};
 \draw[innerblue,densely dashed] (0,0) circle (.85);
 \draw[outerorange] (0,0) circle (1.7);
 \draw[innerblue!60,densely dotted] (0:.85) -- (120:.85) -- (240:.85) -- cycle;
 \draw[outerorange!60,densely dotted] (53.13:1.7) -- (-53.13:1.7);
 \draw[outerorange!60,densely dotted] (146.44:1.7) -- (-146.44:1.7);
 \draw[->,innerblue] (0,0) -- (60:.85)
  node[pos=.55,right,black] {\(r_-\)};
 \draw[->,outerorange] (0,0) -- (-100:1.7)
  node[pos=.82,left,black] {\(r_+\)};
 \foreach \a in {0,120,240}
  \fill[innerblue] (\a:.85) circle (2.8pt);
 \foreach \a in {53.13,-53.13,146.44,-146.44}
  \node[draw=outerorange,line width=.9pt,fill=white,inner sep=2.4pt]
   at (\a:1.7) {};
 \node[anchor=west,align=left] at (2.75,.75)
  {\textcolor{innerblue}{\(\bullet\)} Inner triple at the cube roots of unity,\\
   \phantom{\(\bullet\)} equal weights};
 \node[anchor=west,align=left] at (2.75,-.55)
  {\textcolor{outerorange}{\(\square\)} Outer four: two complex-conjugate pairs\\
   \phantom{\(\square\)} whose phases \(w\) have \(\mathrm{Re}\,w=x,y\) of Eq.~\eqref{eq:sevenphases}};
\end{tikzpicture}