\tracingonline1

\ifx\directlua\undefined\else
\directlua{
% callback.register('define_font',font.read_tfm)
% manual sec 4.2.2, simplified
 callback.register('define_font',function(name,size) local f=font.read_tfm(name,size) return f end)
}
\fi

\font\x=cmr12

\setbox0\hbox{\x va}
\showbox0

abc \box0

\bye

Background
==========
1. Don Knuth finished version 1.0 of TeX in November 1983.
2. At about the same time the TeX Users Group (TUG) was established.
3. TeX became widely used for technical typesetting, by both authors and publishers.

\documentclass[border=2mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric}
\begin{document}

\begin{tikzpicture}
% create the node
\node[draw=none,minimum size=2cm,regular polygon,regular polygon sides=12] (a) {};

% draw a black dot in each vertex
\foreach \x in {1,2,...,8}
  \fill (a.corner \x) circle[radius=2pt];
\foreach [evaluate=\x as \y using int(\x+1)] \x in {1,2,...,7}
  \draw (a.corner \x) -- (a.corner \y);

\end{tikzpicture}
\end{document}