Bach, perhaps more than any other composer I know, strikes me as something like sonic geometry.

A lot of metal gives me a similar impression.

Nods to the post about algorithms above.

Much of Bach's music features improvisation. Does that fit with math?

Classical music is like Parcheesi

I guess that depends on whether math means anything to you in the abstract. The patterns the improvisations base themselves around remind me, in a way, of how algebra equations are structured.

Well yeah. They're both boring as ****.

Literally all music is composed using mathematics. Whether people utilize it instinctivly or deliberately is the only real question.

There is a certain amount of mathematics in the study of the theory of music. Mathematics though is a vast endeavour, with many branches. When people say "music is maths", what they are usually talking about is a very small subset of maths, namely number theory as applied to the notes of whatever scale you are discussing.

I think the idea that "music is maths" would have been news to many of the pioneer folk and blues musicians, who most likely just played and sang whatever sounded good to them, in many cases not even knowing anything about reading or writing musical notation, let alone any mathematical basis behind it.

Short answer: All music has mathematical principles governing the sounds and patterns of the sounds