The movement code producing this beautiful periodic spiral pattern http://i.imgur.com/3Si1Ki5.gif

gistfile1.txt

// ttime is the global timer, a floating point number of seconds

for(int i = 0; i < numSprites; i++){
    sprites[i]->SetAngle(sprites[i]->GetAngle() + .04);
    sprites[i]->SetPosition(spm::vec2(
             anchorPoint.m[0] + 20 * i * sin(i * .01f * ttime),
             anchorPoint.m[1] + 20 * i * cos(i * .01f * ttime)
                 ));
    sprites[i]->Draw(frame);
}