如何用点填充 tcolorbox 的空白

Question

第一个 tcolorbox 是有解决方案的示例。最后三个 tcolorbox 包含没有解决方案的问题，带有虚线。所有 tcolorbox 的高度相同且可破坏。请帮我将代码更正为自动！提前谢谢！

\documentclass[a4paper]{article}
\usepackage{tikz}
\usepackage{tikzscale}
\usepackage{tcolorbox}
\usepackage[utf8]{vietnam}
\tcbuselibrary{raster}
\usepackage{lipsum}
\begin{document}
    \begin{tcbraster}[%
        raster columns=2,
        raster rows=2,
        raster height=\textheight,
        ]
        \begin{tcolorbox}[title={\fontfamily{qag}\textbf{Example 1.}}]
            \lipsum[10]
        \end{tcolorbox}
         \begin{tcolorbox}{\fontfamily{qag}\textbf{Example 2.}} \par
                 \edef\sodongt{\the\numexpr\dimexpr (\tcbtextheight)/(\dimexpr \baselineskip\relax) \relax\relax}
                  \pgfmathsetmacro{\sodong}{int(\sodongt-1)}
                  \foreach \i in {1,...,\sodong}{
                    \dotfill\endgraf
                  }
                \end{tcolorbox}     
               \begin{tcolorbox}
                \edef\sodongt{\the\numexpr\dimexpr (\tcbtextheight)/(\dimexpr \baselineskip\relax) \relax\relax}
                          \pgfmathsetmacro{\sodong}{int(\sodongt-1)}
               {\fontfamily{qag}\textbf{Example 3.}} \par Some text\\
               Some text \sodong
               \foreach \i in {1,...,\sodong}{
                            \dotfill\endgraf
                          }        
               \end{tcolorbox}
               \begin{tcolorbox}
               \edef\sodongt{\the\numexpr\dimexpr (\tcbtextheight)/(\dimexpr \baselineskip\relax) \relax\relax}
                                  \pgfmathsetmacro{\sodong}{int(\sodongt-1)}
                       {\fontfamily{qag}\textbf{Example 4.}} \par Some text\\
                       Some text 2\\
                        Some text 3\\
                       \foreach \i in {1,...,\sodong}{
                                    \dotfill\endgraf
                                  }           
               \end{tcolorbox}
    \end{tcbraster}
\end{document}