What do these icons mean?

Thanks Stan,

I went through all of the videos you provided. None of them really get to my question. The little UI icons must mean something, otherwise the icons could all be the same icon, right?

I’m particularly interested in the square icons with the two lines inside. Sometimes there is just an empty square, sometimes the lines in the square are vertical, and sometimes the lines in the square are horizontal. What does that mean?

Thanks,
Chris