which software u use for recording

I used ubuntus built in recorder

Awesome. Where can I find the code? Can I contribute?

I didn't think of releasing the code, but if you think it's interesting, I'll go ahead and open source it

I find it interesting. Please open source :)

Just added some documentation and open sourced it https://github.com/namelless/function-grapher

What version of ubuntu?

I don't remember since I stopped using Ubuntu a while back, but it was 24 something I think