Hearing infinity

I frequently get emails from people who have read my books (usually satisfied customers!) - but the other day, for the first time, I was contacted by someone who had enjoyed listening to one - the audio book version of A Brief History of Infinity.

Something that was particularly encouraging about hearing from Richard Madigan in New York was that the audio experience was sufficiently clear that he felt inspired to produce the graphic below of Galileo's 'parallel wheels' thought experiment.

For some reason I had always imagined it turning the other way, but it's fun having a concept in an audio book made very elegantly visual this way.

Here's the GIF: