Thanks for that link. Super useful. Looks like BigML uses same layout I did for ANTLR parse trees. Really packs stuff in; e.g., https://cdn-images-1.medium.com/max/1760/1*k0mO4kJyQvPCyyev0...
https://en.m.wiktionary.org/wiki/Reingold-Tilford_algorithm
Really good algorithm to have in an arbitrary visualization toolkit.