Toppling Loci Topple a square along a line. Draw the locus of one corner of the square. How many topples does it take to get the square back to its starting orientation? What is the length of the locus? Now use a triangle instead of a square. Or a rectangle. Or another shape. Or find the locus of the centre of the square. More Toppling Loci Topple a square round another square. Draw the locus of one corner of the square. How long is the locus? What about a triangle round a triangle? A square round a hexagon? Polygons along a line Topple a regular polygon along a line. Choose the size of the polygon so that the radius of the circumcircle is 1 unit. What is the length of the locus of a corner for one rotation of the polygon? What is the area enclosed between the locus and the line? What about an Nsided polygon? What happens when N tends to infinity? Polygons around polygons Now topple a regular polygon round an identical regular polygon. What is the length of the locus of a corner? What is the area enclosed by the polygon? What about an N-sided polygon?’ What happens when N tends to infinity? Inside and outside Topple a unit square round a 2-by-2 square. What is the length of the locus of one corner? Is there more than one answer? What about a 3-by-3 square? Other squares? Now topple a unit square inside a 2-by-2 square. A 3-by-3 square. Other squares. Are any of your inside locus lengths the same as your outside locus lengths? Can you explain? Now try toppling a square round or inside a rectangle.