Are You a Screwball? Metaphors

A post at York Town Square provides a definition of "screwball", the definitive one.  It sounds logical to me, though a fast search doesn't reveal any confirmation.  But I know filter screens can clog, and I can imagine bouncing balls could vibrate it enough to keep it clear, and such motion (brownian, perhaps) would be erratic, erratic enough to lead to the modern definition of "screwball".