You can't do this and you can't do that - signs like this irritate children everywhere. So when the pupils at Kingsford Primary in Aberdeen got the opportunity to come up with their own signs, marked BY ORDER OF ME, they really went for it.
Their work has been on display in a sequence of 20 signs, forming a public art installation on top of Broad Hill, overlooking Aberdeen beach. Anyone who makes the effort to walk up will be guaranteed a smile for the journey down.
Nine-year-old Courtney Fraser from P45 explains: "Most of the signs around this place tell you not to do something. We wanted to make them so it tells you that you can do something."
Courtney's sign says: "Close your eyes - it doesn't make a difference".
Another, by her friend Ansu Saji, nine, says: "Take off your shoes and feel the mud on your socks".
The installation is titled BY ORDER OF ME and the children worked alongside visual artist Rachel O'Neill and writer Davey Anderson to develop their ideas.
The results encourage a more positive approach to life than Keep Off the Grass or No Ball Games and reflect the children's free-spirited response to their environment.
"It's been great fun. It's just children thinking outside the box and thinking what would make things different for us?" says Jayne Watson, depute headteacher at Kingsford.
The venture is part of Extreme, a citywide arts project led by Aberdeen City Council's arts education team and the National Theatre of Scotland. Extreme has been running since August 2010 and culminated in a large-scale theatre production at Linksfield Community Centre at the end of March.