That reminds me of a similar joke:
A childless couple went to visit a gadol for a bracha whilst they were visiting E”Y. The gadol said he would put a kvittel into the kosel for them, and the couple left, satisfied.
Five years later, they were back in E”Y for a holiday and the wife met the gadol again. He remembered her and asked how they were. She replied that they were doing fine: B”H they’d had twins ten months later, then triplets a year after that, and then another child and one more set of twins very close together.
“Baruch Hashem!” the gadol said. “And where is your husband?”
The wife replied, “He’s gone to the kosel to find that piece of paper!”