If you had letters that were flying around, then some could just fly outside the camera's view. Poof! Their gone. While others fly-in in their place to form the new word. Or as a letter passes behind another, change it's visibility to off, and have the new letter waiting to take over it's trajectory and turn it's visibility to on at the next frame. A LOT can happen between frames that client/veiwers don't need to know about. ;) With the explode modifier, as one explodes to nothingsness, change it's visibility, and the new letter, (with the reversed modifier,) change it's visibility to on and un-explode into place. Experiment, have fun, and please post whatever you find works best. We'd love to see it!