Anonymous 1123
This is my code that I drew a cylinder is inscribed in a prism.
```
\documentclass[border=1mm,12pt,tikz]{standalone}
\usetikzlibrary{calc,3d,angles}
\usepackage{tikz-3dplot}
\usetikzlibrary{intersections,calc,backgrounds}
\usepackage{fouriernc}
\begin{document}
\def\a{4}%
\def\R{4}%
\def\h{4}%
\pgfmathsetmacro{\myr}{1}
\foreach \X in {10,20,...,350}
{\tdplotsetmaincoords{70}{\X}
\begin{tikzpicture}[tdplot_main_coords,line join = round, line cap = round]
\begin{scope}[canvas is xy plane at z=0]
\coordinate (O) at (0,0);
\coordinate (A) at (-1, -1);
\coordinate (B) at (2, -1);
\coordinate (C) at (-1, 3);
\draw[dashed] (\tdplotmainphi:\myr) arc(\tdplotmainphi:\tdplotmainphi+180:\myr);
\draw[dashed] (\tdplotmainphi:\myr) coordinate(BR) arc(\tdplotmainphi:\tdplotmainphi-180:\myr) coordinate(BL);
\end{scope}
\begin{scope}[canvas is xy plane at z=\h]
\coordinate (O') at (0,0);
\coordinate (A') at (-1, -1);
\coordinate (B') at (2, -1);
\coordinate (C') at (-1, 3);
\draw [dashed](BR) -- (\tdplotmainphi:\myr) (BL) -- (\tdplotmainphi-180:\myr); % vẽ hai đường sinh
\draw[thick] (\tdplotmainphi:\myr) arc(\tdplotmainphi:\tdplotmainphi+180:\myr);
\draw[thick] (\tdplotmainphi:\myr) coordinate(BR) arc(\tdplotmainphi:\tdplotmainphi-180:\myr) coordinate(BL);
\draw [thick](BR) -- (\tdplotmainphi:\myr) (BL) -- (\tdplotmainphi-180:\myr); % vẽ hai đường sinh
\end{scope}
\foreach \v/\position in { B/below,O/right,A/left,B'/above,O'/right,A'/above,C/below,C'/above} {\draw[draw =black, fill=black] (\v) circle (1pt) node [\position=0.2mm] {$\v$};
}
\draw[dashed] (O) -- (O') (B) --(A) --(C) (A) -- (A');
\draw[thick] (A') --(B') -- (C')-- cycle (B) -- (B') (C) -- (C');
\draw[thick] (B) -- (C) ;
\node[anchor=north east] at (current bounding box.north east) {$\theta=\tdplotmaintheta^\circ,\phi=\tdplotmainphi^\circ$};
\end{tikzpicture}}
\end{document}
```
How to draw it with `3dtools`?