Dos ventanas en un tejado

Question

Me gustaría utilizar tikz 3d library, si es posible, para dibujar fácilmente estas dos ventanas en el techo. Leí las publicaciones sobre esta biblioteca pero no entendí cómo hacer esto.

\documentclass[tikz,border=5mm]{standalone}
%\usetikzlibrary{calc,3d}

\begin{document}

\begin{tikzpicture}[line join=round,
    x={(30:1cm)},
    y={(165:1cm)},
    z={(0cm,1cm)}]

\draw (0,0,0) -- (2.5,0,0) -- (2.5,0,-1.3) -- (0,0,-1.3) -- cycle ;
\draw (0,0,0) -- (0,5,0) -- (0,5,-1.3) -- (0,0,-1.3) -- cycle ;
\draw (0,0,0) -- (1.25,.9,1.8) coordinate (H1) --(2.5,0,0) ;
\draw (0,5,0) -- (1.25,4.1,1.8) coordinate (H2) -- (1.25,.9,1.8) ;

\begin{scope}[shift={(0,2.7,1)}]
\draw (0,0,0)--(0,.5,0)--(.417,.5,.6)--(.417,0,.6) -- cycle ;
\end{scope}

\begin{scope}[shift={(0,.9,1)}]
\draw (0,0,0)--(0,.5,0)--(.417,.5,.6)--(.417,0,.6) --cycle ;
\end{scope}

\end{tikzpicture}
\end{document} 

Answer 1

Una choza vergonzosamente destartalada en comparación conla casa de david...

\documentclass[tikz,border=5]{standalone}
\usetikzlibrary{calc}
\begin{document}
\begin{tikzpicture}[x=(345:1cm/sqrt 2),y=(215:1cm/sqrt 2),z=(90:1cm)]
\fill [gray!50] (-8,5,0) -- (-8,5,8) -- (8,5,8) -- (8,5,0) -- cycle;
\fill [gray!25] (8,5,0) -- (8,5,8) -- (8,-5,8) -- (8,-5,0) -- cycle;

\fill [red!25]  (9,6,8) -- (9,-6,8) -- (5,0,12) -- cycle;
\fill [red!50] (9,6,8) -- (-9,6,8) -- (-5,0,12) -- (5,0,12) -- cycle;

\path (-5,6,8) -- (5,6,8) 
  coordinate [pos=0.125] (a) coordinate [pos=0.375] (b)
  coordinate [pos=0.625] (c) coordinate [pos=0.875] (d);
\path (-5,0,12) -- (5,0,12) 
  coordinate [pos=0.125] (a') coordinate [pos=0.375] (b')
  coordinate [pos=0.625] (c') coordinate [pos=0.875] (d');

\fill [cyan!25] ($(a)!0.33!(a')$) -- ($(a)!0.66!(a')$) -- 
  ($(b)!0.66!(b')$) -- ($(b)!0.33!(b')$) -- cycle;
\fill [cyan!25] ($(c)!0.33!(c')$) -- ($(c)!0.66!(c')$) -- 
  ($(d)!0.66!(d')$) -- ($(d)!0.33!(d')$) -- cycle;
\end{tikzpicture}
\end{document}