%@AUTEUR:Guillaume Connan

prologues:=2;

verbatimtex
%&latex
\documentclass{article}
\usepackage[upright]{fourier}
\let\ve\vec
\begin{document}
etex

input geometriesyr16

figure(-10cm,-5cm,12cm,10cm); 
%addition de deux vecteurs(parallelogramme) 
pair t,r,s; 
t=(2u,1u); 
r=(-2u,3u); 
transform T,R; 
T= identity shifted t; 
R= identity shifted r; 
z0=(0,0);z1= z0 transformed T; 
z2=z0 transformed R;z3=z1+z2;
drawarrow z0--z1 withcolor 0.6white; 
drawarrow z0--z2 withcolor 0.6white; 
drawarrow z0--z3 withcolor 0.4white withpen pencircle scaled 1.8bp; 
label.bot(btex $A$ etex, z0); 
label.rt(btex $B$ etex, z1); 
label.top(btex $D$ etex, z2); 
label.top(btex $C$ etex, z3); 
label.bot(btex $\ve{u}$ etex, 0.5[z0,z1]); 
label.bot(btex $\ve{v}$ etex, 0.5[z0,z2]); 
label.lft(btex $\ve{u}+\ve{v}$ etex, 0.7[z0,z3]);

draw z2--z3 dashed evenly;
draw z1--z3 dashed evenly;
fin;

end