Quoted COVID-19 Diary - Lily pads and exponential thinking by David Walsh (Owner of the Museum of Old and New Art - MONA) (blog.mona.net.au)

Here's a problem: a lily pad grows in an otherwise empty pond. The lily pad produces a new pad every day, the same size as the original. They both reproduce the next day, so that on the first day there is one lily pad; the second day, two; the third day, four; and so on. The pond is completely covered with lily pads by the thirtieth day. On what day did lily pads cover half the pond? If you don't immediately realise it was the twenty-ninth day, you are not equipped to deal with the exponential growth of COVID-19.

It’s not a long read, and it’s worth reading. The first few paragraphs might not interest many people – especially those outside of Australia, but 1/3 in is where the interesting things happen.