I remember this! It was one of my inspirations for creating a hierarchical state machine editor [0] and a state machine library with a visualization layer [1].

I remember this! It was one of my inspirations for creating a hierarchical state machine editor [0] and a state machine library with a visualization layer [1]. [0] https://state.new https://state.new [1] https://github.com/statelyai/xstate https://github.com/statelyai/xstate