I spotted a little riddle – I do not have an answer, yet.
I have never seen the family name written on the reverse in a similar style to this with standard letters (O, U, H, L, A, and I); upside-down letters (C, G and B) and mirrored-letters (S and N). I have seen a play on N’s but never so many as this.
Maybe it is a family joke.
Maybe someone in the family is a type-setter or engraver and wanted some fun.
I cannot believe that it was accidental – especially with both N’s and S’s treated similarly.
If the intent was to cause the reader to pause longer at the grave and think of the residents, it succeeded.
Update 2017.01.30
GraveyardDetective told of similar incidence in Harrogate, where he was told by vicar and warden that the stone mason disliked the person named on headstone.
Poor Frank Raw commented that it was ‘Inexperienced youth setting out (backwards) letters for pressing into concrete.’