// import geometry_dev; // extension devenue l'extension geometry officielle
import geometry;        // le 12/05/09, dans la version 1.71 d'asymptote. :-))

unitsize(1cm);

// ~~~~~~ DEFINITIONS ~~~~~~~~~~~~~~~~~~~~~~

pair pO=(0,0), pI=(1,0), pJ=rotate(45,pO)*pI;
line d1 = line(pO,pI);
line d2 = line(pO,pJ);

// Définition d'un repère non orthogonal
currentcoordsys = cartesiansystem(pO,i=pI,j=pJ);

int n1min=-2, n1max=5, n2min=-3, n2max=6;

point pA=(2,0), pB=(4,0), pC=(0,3), pD=(0,5);

// ~~~~~~ CONSTRUCTIONS ~~~~~~~~~~~~~~~~~~~~~~

label("$O$",pO,S);
draw(d1^^d2);

for (int i=n1min; i <= n1max; ++i)
  {
   dot(locate((i,0)));write(i);
  }
for (int i=n2min; i <= n2max; ++i)
  {
   dot(locate((0,i)));
  }

dot("$A$",pA,S);
dot("$B$",pB,S);
dot("$C$",pC,NW);
dot("$D$",pD,NW);

shipout(bbox(xmargin = 1mm,invisible));