The Steiner problem, or as it is also known colloquially, the motorway problem , is a perennial favourite in mathematics with real-world applications. How do you get from A to Z via any number of intermediate towns and cities covering the least number of total miles? Mathematicians and computer scientists have spent decades trying to find a solution, because the problem couched in terms of building roads, laying pipelines, connecting up networks etc, could allow countless engineering and other projects to be carried out much more efficiently than using conventional wisdom or best guesses.

So, if we’re looking for a solution, how about adding soap? Mathematician, juggler and comedy nerd “SingingBanana”, a.k.a. James Grime, shows us how. This is serious stuff.

Ironic that he’s a mathematician called Grimes who used soap to clean up the problem.