Guerra had a grapevine, and Parra had a dog, and Parra's dog bit Guerra's grapevine, so Guerra beat Parra's dog with a club. —Tell me, Mister Guerra: Why have you beaten the dog with your club? —Because if Parra's dog hadn't bitten Guerra's grapevine, Guerra wouldn't have beaten Parra's dog with the club.
Source: tatoeba (10817032)