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% !TEX lualatex
\documentclass{standalone}
\usepackage{luamplib}
\everymplib{beginfig(1);}
\everyendmplib{endfig;}
\begin{document}
\begin{mplibcode}
path P;
P = (0,0){right} .. (2cm,4cm){up} .. (4cm,5cm){right} .. (5cm,6cm){up} .. (8cm,7cm){right};
draw P withpen pencircle scaled 2pt withcolor .7 white;
s = 5mm;
for t=0 step s until arclength P:
drawdot point arctime t of P of P withpen pencircle scaled 4pt withcolor red;
draw (point arctime t of P of P)--(point arctime t of P of P+direction arctime t of P of P);
endfor
\end{mplibcode}
\end{document}
% Local Variables:
% TeX-engine: luatex
% End:
