Sounds like Fox has something to say.

Just an idea........... Put up loads of bits of paper on the wall that Fox keeps trying to draw on. I think it is unfair to stop Fox drawing, Fox needs an outlet to express things. Leave crayons or chalk for him to use. Keep sharp objects out the way. Leave old newspapers around for him to rip up.

Next time you go shopping buy a chalk board and chalks, big bits of paper, and art supplies that are usually made for children. ie non-toxic and safe.