Merely SoundsV2 of https://merely.xyz/waves is now live and it has FM! This means new possibilities for sounds and shapes. It also brings improved UI, and for supporters: scw export & more segments. Enjoy!
To play with frequency modulation, convert any segment (except the first one) to a modulator.
I'm happy that the concept of FM plays well with the rest of the app, and especially that it has a valid (and pretty) visual representation in this context.