//////////

    //

    // add a few override samples to move the space ship and icon, and to change the icon's layer

    //

    //////////

    // original space ship location

    myIndex         = kFirstSpaceShipImageIndex;

    myLocation.h    = 0;

    myLocation.v    = 80;

    isVisible       = true;

    for (i = 1; i <= kNumOverrideSamples; i++) {

        // remove existing atoms (which we used above

        // to create our key frame sample) from our key

        // frame sample atom container so we can re-use

        // the atom containers for our override samples

        QTRemoveChildren(mySample, kParentAtomIsContainer);

        QTRemoveChildren(mySpriteData, kParentAtomIsContainer);

        // every third frame, bump the space ship's image index (so that it spins as it moves)

        if ((i % 3) == 0) {

            myIndex++;

            if (myIndex > kLastSpaceShipImageIndex)

                myIndex = kFirstSpaceShipImageIndex;

        }

        // every frame, bump the space ship's location (so that it moves as it spins)

        myLocation.h += 2;

        myLocation.v += 1;

        if (isVisible)

            SetSpriteData(mySpriteData, &myLocation, NULL, NULL, &myIndex, NULL, NULL, NULL);

        else {

            isVisible = true;

            SetSpriteData(mySpriteData, &myLocation, &isVisible, NULL, &myIndex, NULL, NULL, NULL);

        }

        AddSpriteToSample(mySample, mySpriteData, 2);

        // make the icon move and change layer

        // first remove previous children from our container

        // so we can re-add the new sprite property atoms

        QTRemoveChildren(mySpriteData, kParentAtomIsContainer);

        // change the icon location

        myIconLocation.h += myDelta;

        if (myIconLocation.h >= myIconMaxH ) {

            myIconLocation.h = myIconMaxH;

            myDelta = -myDelta;

        }

        if (myIconLocation.h <= myIconMinH ) {

            myIconLocation.h = myIconMinH;

            myDelta = -myDelta;

        }

        // change the sprite layer

        if (myDelta > 0)

            myLayer = 0;

        else

            myLayer = 3;

        // set the data for the sprite

        SetSpriteData(mySpriteData, &myIconLocation, NULL, &myLayer, NULL, NULL, NULL, NULL);

        AddSpriteToSample(mySample, mySpriteData, 4);

        AddSpriteSampleToMedia(myMedia, mySample, kSpriteMediaFrameDuration, false, NULL);  

    }

    EndMediaEdits(myMedia);

    // add the media to the track

    InsertMediaIntoTrack(myTrack, 0, 0, GetMediaDuration(myMedia), fixed1);