If you started using your desk items as a weapon and swung them at a person in a manner that could reliably kill them then the court would consider you to have a deadly weapon as well.
If you use an item in a manner that can reliably kill people then you use a deadly weapon even if it wasn't intended to be a deadly weapon. Is a pair of scissors a deadly weapon? Yes. Is a heavy hard blunt object (like a statue) a deadly weapon? Yes.