[Solution]
Solution: There are a number of clues that hint towards the solution of this pencil case:
The brand name “mephone” and the doodle of “one impossible thing” are derived from elements in A Study in Pink and the unaired pilot, to indicate the significance of Jennifer Wilson’s phone.
The sketch of nine ‘T’s, arranged in a 3x3 square is intended to indicate the use of T9 predictive text as an input system (be it ever so anachronistic, given the smart phone premise, but there you have it!)
The word “rabid” is the first prediction given by T9 software when only the first five entries of the word “Rachel” have been made.
The pencil case is divided into six 3x3 squares, each of which represents the keys from 1 to 9 of an alpha-numeric phone pad.
The first five of the 3x3 squares have been given cross-stitch “entries” that correspond to the first five keys that would be pressed to type “Rachel” using T9 predictive text. (The last character is missing.)