The geometry is an unit square with two different tags above and below the diagonal, so there is an internal surface.
The target anisotropic cell size are
$h_x = 0.5$ -
$h_y = h_0 + 2 (0.1 - h_0)|y - 0.5|$ with$h_0 = 0.001$
The initial mesh only contains two triangles. 4 iterations are performed to avoid differences with the metric interpolation.
