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

[ 1]● ==> H8   [ 2]○ ==> I8   [ 3]● ==> J10  [ 4]○ ==> I9   [ 5]● ==> K9
[ 6]○ ==> I11  [ 7]● ==> I10  [ 8]○ ==> K10  [ 9]● ==> L11  [10]○ ==> H9
[11]● ==> F9   [12]○ ==> G11  [13]● ==> F11  [14]○ ==> H10  [15]● ==> J8
[16]○ ==> J12  [17]● ==> K13  [18]○ ==> H12  [19]● ==> G12  [20]○ ==> F12
[21]● ==> E13  [22]○ ==> J14  [23]● ==> I13  [24]○ ==> H11  [25]● ==> H13