Sounds intriguing. What is an example of a chart and its language that you have designed so far?

The Piano chart on prototype is an example, that's for discussing piano keys and chords on basic level.

I already implemented (in other prototype) diagram for event calculus (i.e. consideration of event stream through addition of new events like rollback, modify etc.)

On paper I have designs for point-in-time designs, scenario divergence and also some fun ones like a bingo card template. Diagrams are one thing, but there's also a design for collaboration and play-replay capabilities.

That being said, that's only a design right now with a simple prototype on the website :)