It has been a while since I have posted here—a combination of work and personal commitments and stresses. But I miss writing, and I hope you, my readers, miss my posts.

COVID-19 is slowly being normalised, and hence, there are fewer occasions to write about epidemiology and statistics. But this blog has never been only about Covid-19, so it is a good time to return to its main purpose—writing about mathematics and statistics.

As I hope to get back into regular blogging, I want to start a new series, *A Graph a Day*, where I regularly show an interesting graph with a short comment. It is probably too ambitious and unrealistic to expect a graph daily, but I will do my best to do it regularly.

I am still planning to write longer posts on using mathematics and statistics in epidemiology, but they will appear on Substack – particularly as it now allows mathematical formulas.

So, welcome to the first release of *A graph a day…*

I found this picture fascinating. It shows that international trade is like water—if you block one channel, it will find another. Unfortunately, this also shows that unless the trade restrictions are very strict (i.e. a physical blockade, or a very broad international consensus), they are not likely to work. The price of the goods will surely go up, but the trade will continue.

I also find the oscillations in the yearly trade to Russia, both from the UK and from Germany, fascinating. I am sure that there are good reasons for it – particularly as we are not talking large numbers (£30m probably means 1,000 cars per year) – but wondering what an AR process fitted to the data would look like…