This year marks the 300th birthday of the legendary mathematician Leonhard Euler. Plus will be celebrating this with a series of articles, but if you want to give your eyes a rest and use your ears, then tune into BBC Radio Four's Material World on Thursday the 15th of March at 4.30pm. Half the program will be on Euler and will feature Plus authors Julian Havil and Robin Wilson. If you read this entry after the event, you can listen again on the BBC website.