12. The computer system as recited in claim 9 , wherein the first and second locations each include coordinate locations on the multi-touch input display surface that are abstracted from areas of the first and second contact on the multi-touch input display surface, respectively.
12. The computer system as recited in claim 9 , wherein the first and second locations each include coordinate locations on the multi-touch input display surface that are abstracted from areas of the first and second contact on the multi-touch input display surface, respectively. 13. The computer system as recited in claim 12 , wherein the first and second contact each occur between a human hand and the multi-touch input display surface.