\ifx\undefined\eplain \input eplain \fi

Here is a single-column line of text.
%\vskip 6in
%And another one.
 
\doublecolumns
\newcount \xxx
\xxx=0
\par
\baselineskip = 2.5\baselineskip
\loop
	\hbox{Line \the\xxx.}
	\ifnum \xxx < 3
	\advance \xxx by 1
\repeat
 
\singlecolumn
Another single-column line of text.

\bye