# Format borders for single cells in table

I would like to create a table that looks like the following:

I do not know how to create different borders for each cell. This is what I have so far:

\documentclass[a4paper, 12pt]{article}

\begin{document}
\begin{tabular}{|c|c||c|c|}
\hline \hline
& \textbf{Investigation 1} & \textbf{Investigation 2} & \\
\hline \hline
& \textbf{Angle at midpoint} & \textbf{Left distance} & \textbf{Right distance}\\
\hline
Configuration 1& & &\\
\hline
Configuration 2& & &\\
\hline
Configuration 3& & &\\
\hline
\end{tabular}
\end{document}

• Your image can't be displayed, because it has errors, says a message… – Bernard Jun 21 '17 at 12:08

You can get the double lines indicated in the figure by using hhline.sty. I have assumed that the two right columns both belong to Investigation 2.

\usepackage{hhline}
[...]
\begin{tabular}{|c|c||c|c|}
\hhline{~|t:=:t:==:t|}
\multicolumn{1}{c||}{} & \textbf{Investigation 1} & \multicolumn{2}{c||}{\textbf{Investigation 2}} \\
\hhline{~|b:=::=:=:b|}
\multicolumn{1}{c|}{} & \textbf{Angle at midpoint} & \textbf{Left distance} & \textbf{Right distance}\\
\hhline{--||--}
Configuration 1& & &\\\hhline{--||--}
Configuration 2& & &\\\hhline{--||--}
Configuration 3& & &\\\hhline{--||--}
\end{tabular}


It should also be mentioned that the table will get a more professional look with booktabs.sty.

\usepackage{booktabs}
[...]
\begin{tabular}{ccccc}
\toprule
& \textbf{Investigation 1} && \multicolumn{2}{c}{\textbf{Investigation 2}} \\\cmidrule{2-2}\cmidrule{4-5}
& \textbf{Angle at midpoint} && \textbf{Left distance} & \textbf{Right distance}\\\midrule
Configuration 1 & && &\\
Configuration 2 & && &\\
Configuration 3 & && &\\\bottomrule
\end{tabular}