[[Standalone Note]]
[[Note with]] visible text
[[Some notes]] with visible text [[sandwiched between]]

[[
This text would otherwise be action, but
because it is between an orphaned open and an orphaned close,
all of this is just part of a multiline note.
These lines should probably be assigned
"InvisbleMiddle" or something as its FNLineType.
]]

[[The middle line is
[[Locally a SelfContained]] but becomes an InvisibleOnly
because it is wrapped in a larger multiline note.]]

[[This orphaned open
[[consumes the first open of this ]] SelfContained line, but this visible text remains.

[[This SelfContained line has]] otherwise visible text, BUT
it's consumed by this orphaned close.]]

[[This orphaned open
will not be paired with the
orphaned close down there, because

There is a completely empty line between. So, this line right here is just Action.]]

The above is dumb.
If we are going to have multiline notes, 
just have the opening brackets pair with the next closing brackets.
Why can't there be an empty line between them?

Should we even be trying to write notes in plain text fountain?