%%
%% The LaTeX Companion, 3ed
%%
%% Example 11-4-34 on page II-177 in "amsmath, accents, mathdots --- Various accents".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3examargin}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{135.0pt}

%StartShownPreambleCommands
\usepackage{accents}
%StopShownPreambleCommands

\begin{document}
\[ \accentset{\ast}{X}                 \quad
   \hat{\accentset{\star}{\tilde h}}   \quad
   \underaccent{\diamond}{\mathcal{M}} \quad
   \undertilde{C}\quad\undertilde{M}\quad\undertilde{ABC} \]
\end{document}