Brian, Thanks for your gentle touch, however my vision isn't quite what you discribe below: ---------- > I think that > from that concept, you visualised a situation which I can best describe > as a column of soldiers marching in single file, setting off at equal > intervals, and then the leaders start to slow down so that at some point > they all collide in a big heap, which is where the dyskinesias start. to use the same analogy, I envisage a situation in which it takes as long to lose quarter of the troops as it does to lose half of them, likewise with an eighth of them and then a sixteenth etc, etc. (So far we share the vision). this itself is what I have been refering to as slowing down ie as time passes less soldiers leave in a given time period. I now invision the next platoon of soldiers arriving to find some of the original squad stamping around the parade ground. The two groups combine, resulting in a greater number of soldiers on parade than before. The process continues, with the next squad to arrive finding even more 'residue' (because of starting from a higher base). The numbers grow as squad after squad arrives. Of course my version of events may still be flawed, but at least we should now be on the same parade ground Dennis ++++++++++++++++++++ Dennis Greene 47/10 [log in to unmask] ++++++++++++++++++++