Is there a intermediate checkedbox symbol in LaTeX?

Question

The symbol is like this

I checked the "The Great, Big List of LATEX Symbols" document, but didn't find any similar symbols.

Answer 1

Same size as \square. Works across math styles. The .5 scale of the inner box can be adjusted to suit.

\documentclass{article}
\usepackage{amssymb,stackengine,graphicx,scalerel}
\newcommand\dsquare{\ThisStyle{\ensurestackMath{%
  \stackinset{c}{}{c}{}{\scalebox{.5}{$\SavedStyle\blacksquare$}}
  {\SavedStyle\square}}}}
\begin{document}
$\square\blacksquare \dsquare$

$\scriptstyle\square\blacksquare \dsquare$

$\scriptscriptstyle\square\blacksquare \dsquare$
\end{document}

Answer 2

This is ▣ (U+25A3} in Unicode, and you can use it in fontspec.

Examples

\documentclass{article}
\usepackage{unicode-math}
\setmathfont{STIX Two Math}

\begin{document}
\( \blackinwhitesquare \)
\end{document}

The XITS Math and STIX Two Math fonts have this symbol. You can import only this symbol while using another math font.

\setmathfont{Latin Modern Math} % Or your font of choice.
\setmathfont{STIX Two Math}[range=\blackinwhitesquare,
                            Scale=MatchUppercase}

You can also get this symbol in text mode with fontspec:

\usepackage{fontspec}
\usepackage{newunicodechar}

\newfontface\symbolfont{STIX Two Math}[Scale=MatchUppercase]
\newcommand\blackinwhitesquare{%
  \textnormal{\symbolfont\symbol{"25A3}}
}

\newunicodechar{^^^^25A3}{\blackinwhitesquare} % ▣

Answer 3

It is included in the STIX font. It can be imported without importing the whole font as in the following example.

\documentclass{article}
\DeclareFontEncoding{LS1}{}{}
\DeclareFontSubstitution{LS1}{stix}{m}{n}
\DeclareSymbolFont{symbols}{LS1}{stixscr}{m}{n}
\DeclareMathSymbol{\blackinwhitesquare}{\mathord}{symbols}{"BA}
\begin{document}
\( \blackinwhitesquare \)
\end{document}