Arranging curves

I digitized these curves and used a CAD-program to arrange them in different ways in order to find some kind of clue to the geometry. The curves could roughly be represented as NURBS-curves with two control points in the application Rhinoceros (Rhino).

 Arranged in this way, the endpoints seemed to lie along two circles with the diameter 4/5 of the curves length. The displacement between the circles was 1/4 of the diameter.

I measured angles and distances in order to understand, but could not see any connections.