Figure 9 Two objects that should be joined, how closing removes the break and fills unwanted holes

                 A broken line
  0    0    0    0  0    0    0    0    0    0
  0    0    0    0  0    0    0    0    0    0
  0    0    0    0  0    0    0    0    0    0
  0    0    0    0  0    0    0    0    0    0
200  200  200  200  0  200  200  200  200  200
200  200  200  200  0  200  200  200  200  200
  0    0    0    0  0    0    0    0    0    0
  0    0    0    0  0    0    0    0    0    0
  0    0    0    0  0    0    0    0    0    0
  0    0    0    0  0    0    0    0    0    0

          Closing joins the broken line

  0    0    0    0    0    0    0    0    0    0
  0    0    0    0    0    0    0    0    0    0
  0    0    0    0    0    0    0    0    0    0
  0    0    0    0    0    0    0    0    0    0
200  200  200  200  200  200  200  200  200  200
200  200  200  200  200  200  200  200  200  200
  0    0    0    0    0    0    0    0    0    0
  0    0    0    0    0    0    0    0    0    0
  0    0    0    0    0    0    0    0    0    0
  0    0    0    0    0    0    0    0    0    0

      An object with a hole in it

0  0    0    0    0    0    0    0  0  0
0  0    0    0    0    0    0    0  0  0
0  0  200  200  200  200  200  200  0  0
0  0  200  200  200  200  200  200  0  0
0  0  200  200    0  200  200  200  0  0
0  0  200  200    0  200  200  200  0  0
0  0  200  200  200  200  200  200  0  0
0  0  200  200  200  200  200  200  0  0
0  0    0    0    0    0    0    0  0  0
0  0    0    0    0    0    0    0  0  0

        Closing fills the hole

0  0    0    0    0    0    0    0  0  0
0  0    0    0    0    0    0    0  0  0
0  0  200  200  200  200  200  200  0  0
0  0  200  200  200  200  200  200  0  0
0  0  200  200  200  200  200  200  0  0
0  0  200  200  200  200  200  200  0  0
0  0  200  200  200  200  200  200  0  0
0  0  200  200  200  200  200  200  0  0
0  0    0    0    0    0    0    0  0  0
0  0    0    0    0    0    0    0  0  0