In Cat's Cradle, by Kurt Vonnegut Jr., persons whose lives are tangled up for no very logical reasons are said to belong to the same 'karass'. The table on the following two pages consists of pairs of words which also have this property: although not logically (semantically) related, they are inextricably linked to each other by the fact that together they form a palindrome.
Word Ways: Vol. 12
, Article 2.
Available at: http://digitalcommons.butler.edu/wordways/vol12/iss3/2