When my brother would go into schools to teach about music, the kids loved it when he would tell them to give him a telephone number and he would show them how to turn it into a full blown musical composition, tonal, with orchestration.

In his First Symphony, he introduces all seven themse in the first few measures in an amazing, very mathematical weaving, with melodies turned upside down, backwards, forwards, etc.

He never did that well beyond basic math, but all of his music has a mathematical precision to it which demands the performer pay close attantion, much as Mozart's does.