diff --git a/OG.asy b/OG.asy
new file mode 100644
index 0000000..7cc2047
--- /dev/null
+++ b/OG.asy
@@ -0,0 +1,44 @@
+////////////////////////////////////////////////////////////////////
+/// Des contributions d'OG que je remercie.
+////////////////////////////////////////////////////////////////////
+
+///// Extrémités d'une ligne quelconque sous forme de crochets
+
+void bracket(picture pic, pair a, pair d, real s,pen p=currentpen)
+{
+  picture opic;
+  pair ortd=s*(-d.y,d.x);
+  Draw(opic,(ortd-.5d)--(-0.5d)--0.5d--(.5d+ortd),p+solid);
+  add(pic,opic,a);
+}
+arrowbar BeginBra(real size=0, real ratiob=.3)
+{
+  return new bool(picture pic, path g, pen p, margin margin) {
+real size=size == 0 ? barsize(p) : size;
+bracket(pic,point(g,0),size*dir(g,0)*I,ratiob,p);
+return true;
+  };
+}
+arrowbar Bra(real size=0, real ratiob=.3)
+{
+  return new bool(picture pic, path g, pen p, margin margin) {
+int L=length(g);
+real size=size == 0 ? barsize(p) : size;
+bracket(pic,point(g,L),size*dir(g,L)*I,-ratiob,p);
+return true;
+  };
+}
+arrowbar EndBra(real size=0, real ratiob=.3)= Bra;
+arrowbar Bras(real size=0,real ratiob=.3)
+{
+  return new bool(picture pic, path g, pen p, margin margin) {
+real size=size == 0 ? barsize(p) : size;
+BeginBra(size,ratiob)(pic,g,p,margin);
+EndBra(size,ratiob)(pic,g,p,margin);
+return true;
+  };
+}
+arrowbar BeginBra=BeginBra(),
+Bra=Bra(),
+EndBra=Bra(),
+Bras=Bras();