There may be people old enough to remember chalk at school, or young enough to recall playing with massive sticks of it on the tarmac outside. That’s not relevant in this Archimedes though, as we grapple with renal stones and how to get rid of them (adc.bmj.com/content/103/8/806.1) and how much Vitamin D does a preterm need to have nicely crunchy bones (adc.bmj.com/content/103/8/808).

Does reading that make you think “How much wood does a woodchuck chuck if a woodchuck could chuck wood?”

Anyway - enjoy and share. And send in both your Archimedes and tongue twisters for future editions.