Age 7 to 11
There are lots of answers to this question, depending on what patterns you look for, and how big you think the room is.
Have a try for yourself, and if you discover anything interesting, let us know by emailing email@example.com.
Please don't worry that your solution is not "complete" - we'd like to hear about anything you have tried.
Teachers - you might like to send in a summary of your children's work.