A B C D E F G H I J K L M N O
 15 ┌┬┬┬┬┬┬┬┬┬┬┬┬┬┐ 
 14 ├┼┼┼┼┼┼┼┼┼┼┼┼┼┤ 
 13 ├┼┼┼┼┼┼┼┼┼┼┼┼┼┤ 
 12 ├┼┼┼┼┼┼┼┼┼┼┼┼┼┤ 
 11 ├┼┼┼┼┼┼┼○○┼┼┼┼┤ 
 10 ├┼┼┼┼┼●●●○●┼┼┼┤ 
  9 ├┼┼┼○●○○○●○●┼┼┤ 
  8 ├┼┼┼┼○┼●○●○●┼┼┤ 
  7 ├┼┼┼┼┼●┼●○┼○┼┼┤ 
  6 ├┼┼┼┼┼┼○┼●┼●┼┼┤ 
  5 ├┼┼┼┼┼┼┼┼┼┼┼┼┼┤ 
  4 ├┼┼┼┼┼┼┼┼┼┼┼┼┼┤ 
  3 ├┼┼┼┼┼┼┼┼┼┼┼┼┼┤ 
  2 ├┼┼┼┼┼┼┼┼┼┼┼┼┼┤ 
  1 └┴┴┴┴┴┴┴┴┴┴┴┴┴┘ 

[ 1]● ==> H8   [ 2]○ ==> I9   [ 3]● ==> J6   [ 4]○ ==> G9   [ 5]● ==> J8
[ 6]○ ==> I8   [ 7]● ==> I7   [ 8]○ ==> H9   [ 9]● ==> J9   [10]○ ==> J7
[11]● ==> G10  [12]○ ==> H6   [13]● ==> I10  [14]○ ==> K8   [15]● ==> L9
[16]○ ==> K9   [17]● ==> K10  [18]○ ==> J11  [19]● ==> L6   [20]○ ==> E9
[21]● ==> F9   [22]○ ==> F8   [23]● ==> H10  [24]○ ==> J10  [25]● ==> G7
[26]○ ==> I11  [27]● ==> L8   [28]○ ==> L7