\documentclass[border=5mm]{standalone}
\usepackage{luamplib}
\begin{document}
\begin{mplibcode}
beginfig(1);
 numeric u; u = 21;
 picture strip;
 strip = image(
   for i=-10 upto 10:
     fill unitsquare shifted (2i,0) scaled u;
     draw unitsquare shifted (2i,0) scaled u withcolor 1/2;
   endfor
   for i=0, 1:
     draw ((-20, i) -- (20, i)) scaled u withcolor 1/2;
   endfor
 );
 for i=0 upto 9:
   draw strip shifted (4 normaldeviate, i*u);
 endfor
 clip currentpicture to unitsquare shifted 1/2 left xscaled 29.2 yscaled 10 scaled u;
endfig;
\end{mplibcode}
\end{document}