Undirected Time
This is one of the theoretical ideas out of Halfbakery (here), proposing, that time behaves much like modern Internet, where links are one-directional ("digraph"), and that to make the time be space-like, we just need to add the missing back-links to the web of alternate histories.
Not specified, exactly, how we would add those back-links though. Further ideas how to elaborate on this, are welcome~
+[project]
Undirected time?
Add a backlink to time, then it is bidirectional time, or multidirectional time.
无向时间？ 给时间加一个反向链接，那么是双向时间，或多向时间。
This perhaps should be turned into a category, as it only provides a concept, rather than method.