Trying to create a 2D Surface mesh using 2D Splines

[AndreAhmed]

I'm trying to generate a 2D mesh using 2D splines, but I get the following output:

I use the following code

        splines->AddSpline(sp1, 0, sp1.size());
	splines->AddSpline(sp2, 0, sp2.size());
	splines->AddSpline(sp3, 0, sp3.size());
	splines->AddSpline(sp4, 0, sp4.size());
	splines->AddSpline(sp5, 0, sp5.size());
	splines->AddSpline(sp6, 0, sp6.size());
	splines->AddSpline(sp7, 0, sp7.size());

    meshkernelapi::CurvilinearParameters curvilinearParameters;
    meshkernelapi::SplinesToCurvilinearParameters splinesToCurvilinearParameters;

    splinesToCurvilinearParameters.aspect_ratio = 0.1;
    splinesToCurvilinearParameters.aspect_ratio_grow_factor = 1.1;
    splinesToCurvilinearParameters.average_width = 10000.0;
    splinesToCurvilinearParameters.nodes_on_top_of_each_other_tolerance = 1e-4;
    splinesToCurvilinearParameters.min_cosine_crossing_angles = 0.95;
    splinesToCurvilinearParameters.check_front_collisions = false;
    splinesToCurvilinearParameters.curvature_adapted_grid_spacing = true;
    splinesToCurvilinearParameters.remove_skinny_triangles = 0;
    curvilinearParameters.m_refinement = 20;
    curvilinearParameters.n_refinement = 40;

    // create the algorithm
    meshkernel::CurvilinearGridFromSplines curvilinearGridFromSplines(splines, curvilinearParameters, splinesToCurvilinearParameters);

    // compute
    const auto curviGrid = curvilinearGridFromSplines.Compute();

	meshkernel::Mesh2D mesh(curviGrid.m_edges, curviGrid.m_nodes, meshkernel::Projection::cartesian);

	points_voronoi = vtkSmartPointer<vtkPoints>::New();

	for (auto& v : mesh.m_nodes)
	{
		points_mesh.push_back({ v.x, v.y });


	}
	for (int i = 0; i < mesh.m_facesNodes.size(); i++)
	{
		for (int j = 0; j < 4; j++)
		{
			indices_mesh.push_back(mesh.m_facesNodes[i][j]);
		}
	}

and the Splines are attached here:
L1.txt
L2.txt
L3.txt
L4.txt
L5.txt
L6.txt
L7.txt
L8.txt