Almost 5 year old boy keeps drawing on the walls and doors. I have tried punishing. I have tried providing endless amounts of paper. I have confiscated all writing implements (he still found some, God only knows where from!). I have tried supplying him with many pens, crayons and wax Crayons in a big box with lots of paper and card and activity books. We had a house inspection done by housing and the drawings were obviously noticed. We were told to sort it, given a month to do so. Decorated most of the house. Day before next inspection the little shit he drew all up the stairs again with a pen I have no idea where he had it stashed. So been allowed another month to 'finish sorting the drawings' at which point if there is still drawing on the walls the witch is going to present us with a notice to seek possession. So spent all last week painting over drawings again. We have explained this to the child, he promises he won't do it. Explained to the other 3 children that any pens or crayons they find are to be given straight to mummy or daddy. So today he has done it again 
Ideas?? Please??