Here is your challenge: build the tallest, free-standing structure you can in 900 seconds. Your materials are miniature marshmallows and dried spaghetti. The height of the tower is scored as one point per centimeter.
Your time starts now.
The way in which children approach The Marshmallow Tower Challenge never ceases to amaze me.
Once they have worked out how many minutes they have to play with, their sense of purpose and level of commitment to the task is mesmerising. The industry and buzz in the classroom is electric. As children start to build, they share ideas and ways of working. Some plan, some argue and some seem to work by telepathy.
The end results are a pot-pourri of creativity. When the whistle blows, children take a moment to breathe and assess each group's edible edifice.
We talk through what has worked and what hasn't and discuss ways of altering the structure. After learning from each other and debating different styles, children come to understand that squares are weak and triangles are strong. A look round the room shows pyramid structures stand up to the job better than cuboids.
Now try it again. This time you have 600 seconds. Go!
John Dabell is a numeracy consultant and teacher trainer