An apparatus, system, and method includes a socket having a substantially
spherical inner contour being accessible via an opening. A member having
a partial spherical shape substantially similar to the spherical inner
contour. A cross-sectional profile of the member is adapted to pass
through the opening into the socket and to remain uncoupled with the
socket when the socket and the member are in a first relative
orientation. The member is further adapted to couple with the socket when
the member is in the socket and in a second relative orientation with the
socket.