Research subsequent to Baker (1985) has shown that there are some apparent violations to the Mirror Principle and that there are more operations involved in the determination of the final linear order of morphemes. Firstly, the left adjunction requirement of head movement has been relaxed, as right adjunction has been shown to be possible (Harley 2010 among others). Therefore, different heads can have a specification for right vs. left adjunction. We could imagine, for example, that there is a language in which head movement of the noun to the Number head is specified for right adjunction, rather than left adjunction which is the case in English. In that language, the predicted order of the noun and plural morpheme would then be "s-cat". Notice, however, that right vs. left adjunction determines whether an affix will be realized as a prefix or a suffix: its closeness to the root will still reflect hierarchical order. Let's look at a hypothetical example to make this clear. Assuming that Tense is merged higher than Aspect, there are four possible orders for the tense and aspect morphemes with respect to the verb stem, once we allow for variation between left and right adjunction in head movement.