Just to clarify, I didn’t build anything 
The author of fmlib kindly made the effort to add 7GUIs examples to its doc, which I did suggest because I think it’s a great benchmark overall.
@Frederic_Loyer also kindly posted his 7GUIs implementation for the lablgtk3 lib, which I found very valuable too.
I’d love to see a bonsai impl too, as I did have a hard time and failed to learn it a few months ago.