void perturb(Polygon_2& p, Number_type epsilon) {
Polygon_2::Vertex_iterator vit;
for (vit = p.vertices_begin(); vit != p.vertices_end(); ++vit) {
Point_2 pnt = *vit;
// Make sure we get a consistent perturbation with each point across runs
const static Number_type prime = 827;
srand((int)(pnt.x() + prime*(pnt.y() + prime*pnt.z())));
pnt = Point_25_<Kernel>(perturb(pnt.x(), epsilon), perturb(pnt.y(), epsilon), pnt.z(), pnt.id());
p.set(vit, pnt);
}
p = Polygon_2(p.vertices_begin(), unique(p.vertices_begin(), p.vertices_end()));
}
