core animation rotating covering around erratic point

how i stagger covering controlling core animation around an erratic point? ( box indicate inside covering i wish stagger )

i move doing but changing anchor point, since unless i something wrong each i change anchor indicate also changes position layer.

i attempted something nonetheless didn't work:

[uiimageview beginanimations:nil context:nil];
catransform3d rotationtransform = catransform3didentity;
rotationtransform = catransform3dtranslate(rotationtransform, 0.0, -100.0, 0.0);
rotationtransform = catransform3drotate(rotationtransform, degreestoradians(180),
                        0.0, 0.0, 1.0);
rotationtransform = catransform3dtranslate(rotationtransform, 0.0, 100.0, 0.0)
shape1.layer.transform = rotationtransform;
[uiimageview commitanimations];

it looks series focus relocating during rotate.