+\startuseMPgraphic{HLine}
+path a, b;
+% Create a rectangle of the full size
+a := origin -- (\MPvar{width}, 0mm);
+% Randomize it a bit
+b := a randomized (\overlaywidth / 50) ;
+% And draw it
+drawoptions (withpen pencircle scaled .75mm withcolor black) ;
+draw b;
+\stopuseMPgraphic
+
+% Draw a line with the given options. Accepts only the 'width' option. Be
+% careful that these are metapost options, so use \the\textwidth instead of
+% textwidth, and a metapost expression for arithmethic (e.g. 0.5 *
+% \the\textwidth instead of 0.5\textwidth).
+\def\HLine[#1]%
+ {\setupMPvariables[HLine][#1]%
+ \useMPgraphic{HLine}}
+
+\startuseMPgraphic{HDLine}
+path a, b;
+% Create a rectangle of the full size
+a := origin -- (\MPvar{width}, 0mm);
+% Randomize it a bit
+b := a randomized (\overlaywidth / 100) ;
+% And draw it
+drawoptions (withpen pencircle scaled .75mm withcolor black dashed evenly) ;
+draw b;
+\stopuseMPgraphic
+
+% Draw a line with the given options. Accepts only the 'width' option. Be
+% careful that these are metapost options, so use \the\textwidth instead of
+% textwidth, and a metapost expression for arithmethic (e.g. 0.5 *
+% \the\textwidth instead of 0.5\textwidth).
+\def\HDLine[#1]%
+ {\setupMPvariables[HDLine][#1]%
+ \useMPgraphic{HDLine}}
+
+\startuseMPgraphic{box}
+path a, b;
+% Create a rectangle of the full size
+a := unitsquare xyscaled(\overlaywidth,\overlayheight);
+% Randomize it a bit
+b := a randomized (min(\overlayheight, \overlaywidth) / 25) ;
+% And draw it
+drawoptions (withpen pencircle scaled .75mm withcolor black) ;
+draw b;
+\stopuseMPgraphic
+
+\defineoverlay[box][\useMPgraphic{box}]
+
+% Define \{start,stop}boxed with a nice metapost box around it.
+\defineframedtext[boxed][width=fit,background=box,frame=off]
+