In the sample code below, I'd like to position the WIBBLE text so that each letter in the word is horizontal, and each successive letter in the word appears below the previous letter.
Also, the WIBBLE text should line up with the previous text. I.e. The W in the WIBBLE should line up with the lines containing the "The"'s in the other two columns.
Also, I'd prefer to avoid using graphical libraries like TikZ or MetaPost/MetaFun if possible. The stackengine package looked promising, but its commands don't seem to play well with a tabular format. Maybe it's possible and I didn't use the right formulation.
I found some related material in Vertical "stack" of letters, where every letter is rotated to sit on top of the letter beneath it
@egreg's \stack answer looks very promising, and also clean, simple, and self-contained, but using this the second and third columns move downwards. As I already said, I want it to line up. I see that answer is also using tabular, but I don't currently understand how.
\documentclass[12pt]{scrartcl}
\usepackage{stackengine}
\usepackage{longtable}
\usepackage{xparse}
\ExplSyntaxOn
\NewDocumentCommand{\stack}{O{c}m}
{
\begin{tabular}[#1]{@{}c@{}}
\tl_map_function:nN { #2 } \__tom_stack:n
\end{tabular}
}
\cs_new_protected:Nn \__tom_stack:n { #1 \\ }
\ExplSyntaxOff
\begin{document}
\begin{longtable}{p{2cm}p{8cm}p{8cm}}
& FOX & DOG \\
\stack{WIBBLE}
%\Longstack{W\\I\\B\\B\\L\\E}
& The quick brown fox jumped over the lazy dog
& The quick brown dog jumped over the lazy fox \\
\end{longtable}
\end{document}

\stack[t]{WIBBLE}instead of\stack{WIBBLE}. – Jan 16 '20 at 06:30