SQL Server tables: what is the difference between @, # and ##?

Question

In SQL Server, what is the difference between a @ table, a # table and a ## table?

Answer 1

CREATE TABLE #t

Creates a table that is only visible on and during that CONNECTION the same user who creates another connection will not be able to see table #t from the other connection.

CREATE TABLE ##t

Creates a temporary table visible to other connections. But the table is dropped when the creating connection is ended.