text: size(0,100);
  import patterns;
  
  add("hatch",hatch());
  add("hatchback",hatch(NW));
  add("crosshatch",crosshatch(3mm));
  
  real s=1.25;
  filldraw(unitsquare,pattern("hatch"));
  filldraw(shift(s,0)*unitsquare,pattern("hatchback"));
  filldraw(shift(2s,0)*unitsquare,pattern("crosshatch"));
  