Is your dad a fatherhood genius? Has he expanded the laws of duct tape physics? Is he well-versed in Dad logic? If so, then let Dad know how much you appreciate his fatherly wisdom, even if you never understand it, with these hilarious Einstein Father's Day cards. There's not really proven laws of parenthood, so every Dad is formulating his own equation. This Father's Day, show him you appreciate his fatherly theories with this ingenious Father's Day card.