%! TEX program = lualatex
%
\input{.maindir/tex/header/preamble-section}%
% inputs the preamble only if necessary
\docStart%
\begin{tikzpicture}[scale=\torusscale]
  \tikzinput{lengths}
  \tikzinput{torus-template}
  \node at (0.8, 0.3) {$\hat Q$};
  \foreach \x in {0,...,\nrOfPts}
  \foreach \y in {0,...,\nrOfPts}
  {
    \coordinate (point) at (1/\nrOfPts * \x, 1/\nrOfPts * \y);
    \path (point)+({-360/\nrOfPts*(\x+\y)/2-90}:\halflinelength) coordinate (start);
    \path (point)+({-180-360/\nrOfPts*(\x+\y)/2-90}:\halflinelength) coordinate (end);
    \draw (start) -- (end);
  }
  % overwrite with red
  \foreach \xy in {0,...,\nrOfPts}
  {
    \coordinate (point) at (1/\nrOfPts * \xy, 1/\nrOfPts * \xy);
    \path (point)+(-360/\nrOfPts*\xy-90:\halflinelength) coordinate (start);
    \path (point)+(-180-360/\nrOfPts*\xy-90:\halflinelength) coordinate (end);
    \draw[\boundaryvaluecolor, line width=\thickness] (start) -- (end);
  }
  \tikzinput{torus-diagonal-gamma}
  \tikzinput{torus-corner-coordinates}
\end{tikzpicture}%
\docEnd%