\begin{figure}[tbp]
\centering
\begin{tikzpicture}[>=Latex, line join=round, line cap=round]
\path[use as bounding box] (-0.45,-0.35) rectangle (4.35,2.40);

\appendlight[
  v = return Vector:new{0, 0, 1, 1}
]
\appendtriangle[
  m = return Matrix:new{
    {0, 0, 0, 1},
    {2, 0, 0, 1},
    {0.5, 1.25, 1.0, 1}
  },
  fill options = {fill=ltdtbrightness, draw=black, line width=0.45pt}
]
\appendlabel[
  v = return Vector:new{0.8, 0.35, 0.35, 1},
  text = {$T$}
]
\displaysimplices

\draw[->, orange!85!black, very thick] (1.65,2.05) -- (1.10,1.22);
\node[draw, rounded corners, fill=orange!8, align=left, anchor=west] at (1.78,2.05)
  {a light direction is stored\\before the scene is displayed};

\draw[->, blue!70!black, very thick] (3.20,1.70) -- (1.20,0.66);
\node[draw, rounded corners, fill=blue!6, align=left, anchor=west] at (3.28,1.72)
  {the triangle is appended as\\one geometric record};

\draw[->, teal!70!black, very thick] (3.05,0.48) -- (0.82,0.38);
\node[draw, rounded corners, fill=teal!8, align=left, anchor=west] at (3.12,0.48)
  {the label is stored separately\\and emitted after the geometry};
\end{tikzpicture}
\caption{A first rendered scene. Even this tiny example already exhibits the
package's central pattern: append geometry and labels in any order, then render
everything at once with \texttt{\textbackslash displaysimplices}.}
\end{figure}