How to Build a Gothic Cathedral With 10 People
Persons 1 to 6 stand in pairs facing each other. They raise their hands in front of them and form four-pointed stars (A & B) with their arms by clasping hands. This represents the nave of the cathedral; it is a tall but weak structure. The gaps between the people are to be filled with stained glass.
Place your hands on one of the stars and push down. There will be little resistance, (a) because they are not expecting you to do this and, (b) because the structure is simply very weak. The roof collapses, the glass shatters and the walls crumble.
Now organise persons 7 to 10, two on either side, to put their hands on the backs of persons 1 to 6. They should lean gently but firmly against their friends, as if they are flying buttresses. The added width and support allows the cathedral to be both tall and strong.
Choose one of the smallest people and have them swing from one of the stars to illustrate the point.