Adoption Memes

The ultimate dad joke meets set theory mathematics! The first Venn diagram shows the intersection of sets A and B (the green overlap), which is why the sister is named "A∩B" (the intersection of dad and mom's sets). But the punchline hits when the kid says "thanks dad" and the second diagram shows set A completely outside set B - meaning the kid isn't even in the intersection of his parents' sets. Poor kid just found out he's adopted through mathematical notation! That smug dad smile says it all. Nothing like dropping a paternity bombshell through discrete mathematics!