I tireed to figure ouot the family tree for that one time o.o

I haven't seen this movie in a while,
and the lyrics they used were a little different,
but when I was a kid ( 1960's) this was the song:
I'm My Own Grandpa
Many many years ago when I was twenty-three
I was married to a widow who was pretty as can be.
This widow had a grown up daughter who had hair of red,
My father fell in love with her and soon the two were wed.
This made my dad my son in law and changed my very life,
for my daughter was my mother cause she was my father's wife,
to complicate the matter even though it brought me joy,
I soon became the father of a bouncing baby boy.
The little baby then became a brother in law to dad,
And so became my uncle though it made me very sad,
My wife is now my mother's mother and it makes me blue,
even though she is my wife, she's my grandmother too.
Oh, I'm my own grandpa, I'm my own grandpa.
(Something like that. Working on memory.)