Edit: This post needs a (2017) in the title :) Interesting! I worked on something similar a few years ago. I think I had some good concepts from a long term u

Edit: This post needs a (2017) in the title :) Interesting! I worked on something similar a few years ago. I think I had some good concepts from a long term usability approach, but your engine looks far better. Demo: https://simoji.treenotation.org/ https://simoji.treenotation.org/ Source: https://github.com/breck7/simoji https://github.com/breck7/simoji