继续http://tex.stackexchange.com/a/662018、喂食
\documentclass{article}
\pagestyle{empty}
\usepackage{unicode-math}
\setmathfont{texgyretermes-math.otf}
\begin{document}
\[
\begin{array}{|@{}l@{}|}
L\\
W\\
X\\
Y\\
Z
\end{array}
\mskip6mu
\begin{array}{|@{}l@{}|}
_L\\
_W\\
_X\\
_Y\\
_Z
\end{array}
\mskip6mu
\begin{array}{|@{}l@{}|}
_{^L}\\
_{^W}\\
_{^X}\\
_{^Y}\\
_{^Z}
\end{array}
\]
\end{document}
到 {xe|lua}latex 产生字母