A puzzling problem
"Well, Sam, I'll tell you how it is, you see, I married a widow, and this widow had a daughter. Then my farther, being a widower1, married our daughter, so you see my father is my own son in-law."
"Yes, I see."
"Then again my step-daughter is my step-mother, isn't she? Well, then, her mother is my grandmother, isn't she? I am married to her, am I? So that makes me my own grandfather, doesn't it?"