Many of these have writing on them giving motivational statements on them such as "love life", "get a life" and "get that degree". Some express personal preferences, such as "AN [heart] HC" and "I [heart] Matt X X". A good many are merely the name of the student followed by the date or, occasionally "was here". A few are political statements: I don't know if any members of the Israeli government are likely to pass by here, but if they are then they'll be urged to "free Palestine".
Some of the students exhibit more artistic talent than others. Here are four examples close up:
I suspect that the "Essex food" one was created by a member of the catering team, because the pens for drawing on the stones are in the building's café. However, having eaten Essex food on many occasions, the stone could merely be a comment on how tough the fare here can be.
I'll show you some of what's in the other sections another day. Yes, there are more.