Given 
$delim = = 'A -3 C -4 B';
$set->{'key2'} => ['A -4 B','B -4 C','C -4 A','A -4 B'],

RESULT:
key2
[A -4 B] [B -4 C] /
[A -4 B] [B -4 C] / [C -4 A] [A -4 B]  # only this is correct