I had a bash at printing stone work. Not sure why, well apart from diverting my mind. I found my normal higher detail blue foam wall with lots of texture didn’t work (not in this picture)basically I make a wall out of it. I blasted off another rest tile out of scrap and it was much better. Initially I have used some 10mm blue foam. I have got some foam board so I might give that a go tomorrow on some black/grey card.

My blue foam walls normally look like this.