Use the routine AddAnimOb() to add animation objects to the controlled
object list.  This routine will link the PrevOb and NextOb pointers to
chain all the AnimObs that the system is controlling.

    struct RastPort myRPort;
    struct AnimOb myAnimOb;
    struct AnimOb *animKey;  /* Must be initialized with InitAnimate() */

    AddAnimOb(&myAnimOb, &animKey, &myRPort);