digraph G {
  Curve -> {SurfaceCurve, Pcurve, OffsetCurve3d, OffsetCurve2d, Line, CurveReplica, Conic, BoundedCurve};
  SurfaceCurve -> {SeamCurve, IntersectionCurve, BoundedSurfaceCurve};
  Pcurve -> {BoundedPcurve};
  Conic -> {Parabola, Hyperbola, Ellipse, Circle};
  BoundedCurve -> {TrimmedCurve, Polyline, CompositeCurve, BoundedSurfaceCurve, BoundedPcurve, BSplineCurve};
  CompositeCurve -> {CompositeCurveOnSurface};
  CompositeCurveOnSurface -> {BoundaryCurve};
  BoundaryCurve -> {OuterBoundaryCurve};
  BSplineCurve -> {UniformCurve, RationalBSplineCurve, QuasiUniformCurve, BezierCurve, BSplineCurveWithKnots};
}