Rashi on the Generation of Esav --Why does the Torah teach us the lineage? ah! They're all mamzerim!

Bereishit lamed vav: pasuk bet --Rashi's take on this apparent contradiction of a "bat anah bat tziv'on" is as follows " im bat ana lo bat tziv'on... melameid sheba tziv'on al kaltho, eishet ana, ...vhodiakha hkathuv shekulan bnei mamzeiruth hayu."

My cousin Avi is really my brother; his sister-in-law is really my aunt... so while there is nothing like mamzerut in our family we laughed about this a bit. The relationship is a bit more convoluted, but doesn't fit anything abnormal people might think up. Avi decided to share amidst the laughter the following poem, which I think reads a bit like a funny passage in a gemara -though I have forgotten which maseket. It's a passage which asks one of the possibilities for how amny averot one can committ at a time, if my memory serves me correctly. If anyone knows the aggada that I'm referring to and remembers, please send me the citation!

oy! ****************makes us laugh and think of this poem Avi found called "I'm my own grandpa" credit for author unknown and unclear****************************************

Many, many years ago
When I was twenty-three
I married a widow
As pretty as could be.

This widow had a grow-up daughter
with hair of flowing 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.
Now my daughter was my mother, for
she was my father's wife.

To complicate the matters worse,
Although it brought me joy,
I soon became the father of a
bouncing baby boy.

My little baby then became
A brother-in-law to dad, and
so became my uncle, though
it made me very sad: For

if he was my uncle,
Then that also made him brother to the
widow's grown-up daughter
Who, of course, was my step-mother.

Father's wife then had a son
Who kept them on the run.
And he became my grandson, for
he was my daughter's son.

My wife is now my mother's mother
And it makes me blue, because,
although she is my wife,
She's my grandma, too... If

my wife is my grandmother,
Then I am her grandchild.
And every time I think of it,
It simply drives me wild.

For now I have become the strangest
case you ever saw: As
As the husband of my grandmother, I'm
my own grandpa!