Algorithm 2. The Detailed Design of the Trajectory on a Border
1.	Input di, di+1, cur_dir;     //cur_dir is the current traveling direction of mobile sink
2.	Calculate the length of the trajectory on border lborder_trajectory according to Equation (12);
3.	if (di! = di+1)            //when curve order di ≠ di+1
4.	if (di < di+1)            //curve order is increased
5.	if (cur_dir = left or cur_dir = right)
6.	//current traversing direction of mobile sink is horizontal
7.	direction_on_border←right;
8.	else
9.	direction_on_border←left;
10.	end if
11.	Mobile sink traverses along the direction of direction_on_border with the length lborder_trajectory;
12.	else               //curve order is decreased
13.	if (cur_dir = up or cur_dir = down)
14.	//current traversing direction of mobile sink is vertical
15.	direction_on_border←left;
16.	else
17.	direction_on_border←right;
18.	end if
19.	Mobile sink traverses along the direction of direction_on_border with the length lborder_trajectory;
20.	end if
21.	end if