44. The apparatus of claim 43 wherein the successive locations further include: (vii) at a time later than the time the third starting location occurs and earlier than the time the first ending location occurs, a third ending location not intersecting the particular region; wherein a third period of non-intersection starts in response to the third starting location not intersecting the particular region and ends in response to the third ending location not intersecting the particular region; and wherein the second quantity is further a function of the duration of the third period of non-intersection.
44. The apparatus of claim 43 wherein the successive locations further include: (vii) at a time later than the time the third starting location occurs and earlier than the time the first ending location occurs, a third ending location not intersecting the particular region; wherein a third period of non-intersection starts in response to the third starting location not intersecting the particular region and ends in response to the third ending location not intersecting the particular region; and wherein the second quantity is further a function of the duration of the third period of non-intersection. 45. The apparatus of claim 44 wherein the successive locations further include: (viii) at a time later than the time the third ending location occurs and earlier than the time the first ending location occurs, a fourth starting location intersecting the particular region; and (ix) at a time later than the time the fourth starting location occurs and earlier than the time the first ending location occurs, a fourth ending location intersecting the particular region; and wherein a fourth period of intersection starts in response to the fourth starting location intersecting the particular region and ends in response to the fourth ending location intersecting the particular region; and wherein the second quantity is further a function of the duration of the fourth period of intersection.