HingedAxle is Connections.Pivot.Hinge:
    .doc: """
    By specializing the Hinge connection
    to a HingeAxle connection both objects
    of the Pivot connection are constrained
    to the axle instead of to each other.

    It becomes natural to have this type of connection
    when more than two objects are pivoting about the same axis.
    For example when a hydraulic cylinder actuates
    a linked system and not the object directly.

    """
    with Connections.Pivot.Traits.Axle
    from_hinge is Physics3D.Interactions.Hinge:
        connectors: [axle.central_connector, from]
    to_hinge is Physics3D.Interactions.Hinge:
        connectors: [axle.central_connector, to]
