Mermaid syntax wanted

I'm a programmer. Or was.

I've used mermaid. Here's a test note

Test mermaid

Want to use mermaid to do sequence and class diagrams.

classDiagram
Class07 .. Class08
Class09 --> C2 : Where am i?
Class09 --* C3
Class09 --|> Class07
Class07 : equals()
Class07 : Object[] elementData
Class08 <--> C2: Cool label
classDiagram
Object .. FontBase
FontBase --> Font
Object --> EventDispatcher
EventDispatcher --> Sprite
Sprite --> Shape
Shape --> TextField
FontBase : layoutText()
TextField : setLayout()

— from Mermaid in Joplin? - #37 by bva

— still doesn’t work - Markdown Guide | Joplin

graph LR
    A-->B
    A-->C
    B-->D
    C-->D

but why not just install the Plantuml plugin?

I'm sure the community will sort it out, eventually.