Consider:

http://www.solipsys.co.uk/Giant.png

http://www.solipsys.co.uk/Other.png

These will change as I experiment. Comments welcome.

Interestingly there's no font-styling (or any css for that matter, he is using tables for christ's sake) on that webpage so the reason you are seeing Serif is because of your web browser more than anything else.

It's too old school to expect people to have their own personal default style settings for their browsers. There are barely any sites these days that don't define their own styles.

It's actually a neat idea of the original web, but it's of little practical value today.

He might mean within the graphs. I haven't played with asking neato to change the font being used, and I'm not sure what fonts I have available on my very, very elderly setup.