You are given some matches, a rope, and a pair of scissors.
The rope burns irregularly and takes 60 minutes to burn end to end. however, we know that the burn rate at distance x from the left end is the same as the burn rate at distance x from the right.
What is the smallest time interval that you can measure?

How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?





