In fact, they apply only to personal pronouns, possessive pronouns, and reflexive pronouns. It is only in these types, too, that gender differences are shown (personal he/she, possessive his/hers, reflexive himself/herself). ... Many of the pronouns listed above also belong to another word class - the class of determiners. Pronouns @ The Internet Grammar of English - UCL
Alliteration is a concatenation of words with the same consonant sound; in the expression above, we look out for this sound:/s/; this is found in sat, sideways, simple and smile. Please note: 'she ' doesn't have the consonant /s/ .
