only if the tokens on either side of the blank token are different
e.g. door --> "d" "blank" "o" == "d" "o" but the skip is permited because "d" and "o" are differnt on the either side of the a blank.
only if the tokens on either side of the blank token are different
e.g. door --> "d" "blank" "o" == "d" "o" but the skip is permited because "d" and "o" are differnt on the either side of the a blank.