Long ago, I took a BA in maths at Oxford. After that an MSc at Warwick. I started a PhD also at Warwick but I did not complete it. The topic was ergodic theory. Today, maths is just a hobby.
I studied music in school and took lessons in the clarinet, saxophone, and theory of music. Over many years, I have been trying to teach myself the piano. Progress is slow but I am enjoying it. I rarely play the clarinet or saxophone any more, I don't think that I have enough puff left in my old lungs.
My musical interest is mostly western classical music but quite wide within that genre: from Bach through Beethoven, Stravinsky, and many others to Schoenberg.
I am a dual UK / Irish citizen currently living in the UK. I haved lived in Thailand, Sri Lanka, and the Philippines. I have travelled extensively in Europe and Asia. Also North America and Australia but less so. Never South or Central America and never Africa.
My travel is sometimes for work and sometimes for pleasure. Pleasure travel is often low budget.
Software. Very occasionally I get to use some of the maths than I learned long ago but not often. Music never features in work. I used to travel a lot for work but now just occasionally. I have little interest in chatting about software outside of work and I don't plan to join any software groups.
Mental and physical health
I use maths and music to exercise my brain and try to keep it fit. Similarly, I keep physically fit with badminton, squash, and cycling.