public Polygon2d iterative_offset(GeneralPolygon2d poly, double fDist, int nSteps)
{
int N = poly.Outer.VertexCount;
double max_step = fDist / nSteps;
Polygon2d cur = new Polygon2d(poly.Outer);
for (int i = 0; i < N; ++i)
{
Vector2d n = cur.GetTangent(i).Perp;
cur[i] = cur[i] + max_step * n;
}
return(cur);
}