# Add new comment

Weird and wonderful things can happen when you set a ball in motion on a billiard table — and the theory of mathematical billiards has recently seen a breakthrough.

Was vaccinating vulnerable people first a good choice? Hindsight allows us to assess this question.

A game you're almost certain to lose...

What are the challenges of communicating from the frontiers of mathematical research, and why should we be doing it?

Celebrate Pi Day with the stars of our podcast,

*Maths on the move*!

1. You will be the half-sibling of your half-sibling.

2. You will be the half-aunt or half-uncle of your half-sibling's children, and they will be your half-neices or half-nephews.

3. Your children will be the half-neices or half-nephews of your half-sibling, and your half-sibling will be their half-aunt or half-uncle.

4. Your children will be the half-first cousins of your half-sibling's children, and vice versa.

5. Your grandchildren will be the half-great-neices or half-great-nephews of your half-sibling, and your half-sibling will be their half-great-aunt or half-great-uncle.

6. Your grandchildren will be the half-first cousins once removed of your half-sibling's children, and vice versa.

7. Your half-sibling's grandchildren will be your half-great neices or half-great nephews, and you will be their half-great aunt or half-great uncle.

8. Your half-sibling's grandchildren will be the half-first cousins once removed of your children, and vice versa.

9. Your half-sibling's grandchildren will be the half-second cousins of your grandchildren, and vice versa.