User blog comment:Chronolegends/improved Egg Notation - Analysis/@comment-28606698-20170427070833/@comment-24920136-20170427213413

Right and theres also representation of trees and hydras which uses brackets so the idea isn't by any means novel, also iirc emlightened's notation reaches alot higher when you allow all kinds of bracket, but only ε0 when restricted to a single kind