I've always looked at the line as a connection and the open circle as no connect...

jaywalk on Dec 3, 2019 | parent | context | favorite | on: A comment on Hacker News led to 4½ new Unicode cha...

I've always looked at the line as a connection and the open circle as no connection. It's just what I came up with when I was young as a way to make sense of the markings.