P is a point on the circumference of a circle radius r which rolls,
without slipping, inside a circle of radius 2r. What is the locus
The coke machine in college takes 50 pence pieces. It also takes a certain foreign coin of traditional design...
What happens to the perimeter of triangle ABC as the two smaller
circles change size and roll around inside the bigger circle?
9 identical squares of side 2 units are separated by empty
strips also of 2 units width.
What is the shortest route from A to B, assuming you can only go
around the edges of the squares?
Now, consider 27 identical cubes of side 2 units which are
separated by corridors also of 2 units width. What is the shortest
distance from A to B?