A B C D E F G H I J K L M N O
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  1 └┴┴┴┴┴┴┴┴┴┴┴┴┴┘ 

[ 1]● ==> H8   [ 2]○ ==> I9   [ 3]● ==> H7   [ 4]○ ==> H9   [ 5]● ==> G9
[ 6]○ ==> G8   [ 7]● ==> F7   [ 8]○ ==> I8   [ 9]● ==> J7   [10]○ ==> I7
[11]● ==> I10  [12]○ ==> J8   [13]● ==> H6   [14]○ ==> K7   [15]● ==> H10
[16]○ ==> L8   [17]● ==> H4   [18]○ ==> H5   [19]● ==> F8   [20]○ ==> E7
[21]● ==> F6   [22]○ ==> I5   [23]● ==> I6   [24]○ ==> M5   [25]● ==> L6
[26]○ ==> M9   [27]● ==> J6