[PD] math + music examples

[Joe]

hello
i am trying to come up with some examples to use in a short workshop
with 11 year old kids using maths to make sound and music (music in
very loose terms that is). i would love to use pd for this. it can be
literally anything, as long as they can easily see a relation between
some basic math concepts (number sequences, patterns, etc.) and the
sounds they hear while interacting with the patches. the goal is not
to have the kids write the patches, but to make them *play* with them.

does anyone have any ideas for this? useful, easy to understand math
concepts that could be turned into little musical devices?
any feedback will be greatly appreciated!

cheerio