I’m on a train, and a woman just asked her grandson (about four years old) to put the five bottles on their table in order from biggest to smallest. Starting with the rightmost pair, he carefully considered each pair of bottles in turn, swapping them if they weren’t the right way round. When he reached the leftmost pair he went back to the rightmost pair, and repeated the process until they were all in order. It’s the first time I’ve seen someone carry out a bubble sort in real life.

[Originally posted 21st February 2023 on my previous server]