[GeoffR]

Originally Posted by EndlessWaves

No, infrared can definitely handle more than two touchpoints. There are plenty of larger infrared touchscreens that do ten point multitouch.

If you have three concurrent touches in order 1,2,3 like this:

1 3
  2

Then after touch 1 and 2 there is no way touch 3 can be seen as the sensors are hidden behind the first two touches.

Edit: Perhaps I should have said that infra-red touch can only accurately detect two concurrent touches. Further concurrent touches are subject to errors of the type above.