 This is a mathematical snack from the Association of Teachers of Mathematics for you to enjoy. First of all you need a pile of triangles cut from a square. I'm going to make my square first by folding this piece of A4 paper across and cutting carefully along this side to make the square. You might need somebody to help you with the use of the scissors. So I've already got one fold corner to corner across my square. If I fold the other corner you can see that I'm going to be able to make some triangles from this square. If I cut along this as straight as I can. I'm going to cut these two at the same time from the middle of the side along the fold to that corner. You could of course if you haven't got any paper use newspaper. There are my four triangles and there's my original square. The four triangles are congruent that means they're identical in shape. If I put them on top of each other they are all the same. So what new shapes can I make with these four triangles? I can make a smaller square with those two and I think I can make a rectangle. What if I turn these around and experiment a bit? Here's another shape with four sides. I'm only allowing these full sides touching. That's your challenge. Have a go.