code: function visit(node) {
      if(node.flag) {
        var v = node.value.value
        var adj = v.adjacent
        for(var ptr=elist.level(adj, level); ptr<adj.length && adj[ptr].level === level; ++ptr) {
          var e = adj[ptr]
          var es = e.s
          var et = e.t
          if(es.euler[level].path(et.euler[level])) {
            raiseLevel(e)
            ptr -= 1
          } else {
            //Found the edge, relink components
            link(e)
            return true
          }
        }
      }
      if(node.left && node.left.flagAggregate) {
        if(visit(node.left)) {
          return true
        }
      }
      if(node.right && node.right.flagAggregate) {
        if(visit(node.right)) {
          return true
        }
      }
      return false
    }
docs: Search over tv for edge connecting to tw