@N_Mal, you need to quote your code with backticks (I edited your post to do this):
When you type an expression like @variables without quoting it, you are actually “pinging” a user named variables, just like where I mentioned your username above. The forum software prevents you from pinging too many users in a single post. If you quote the code, however, it knows that @ is part of the code rather than a username reference.