I first started tutoring under the name Salinger’s in Oxford in 1999. After a year, I moved to the United States and returned to school teaching until 2006, when I restarted tutoring in York.

In 2008, I commissioned a portrait of Évariste Galois, a brilliant French mathematician who died in a duel at the age of 20. The portrait was designed by Chris Gylee and hangs in my study at home. It also became the centrepiece of the Salinger’s logo. At the same time I started tutoring in Harrogate as well as York.

Fearing that Salinger’s sounded more like a wine bar than a mathematics tutoring business, I changed the name to dotmaths in 2009. The new logo retained a subtle connection with the old one, with the highlighting of a punctuation mark: the apostrophe became a dot and the other punctuation in the web address was picked out in red.

Finally, in 2011 the arguably boring red square was replaced with an oil painting of a white dot on a red square: the original hangs in my study.