Today is Cinco de Mayo. And this year, the fifth of May is filled with mathematical joy. It is — Square Root Day! It all started in 1981. "I was writing a check in late August," says Ron Gordon ...

Pastrami Beef Tongue Bone Marrow Custard, Fermented Cabbage, Egg Yolk Coriander Foam, Crispy Tongue, Red Cabbage Glace de Veau Philip Lopez, chef-owner of Square Root and his general manager ...

The date so written - 4/4/16 - represents just one of nine so-called Square Root Days every century. The last was celebrated on March 3 2009 and the next one will be marked on May 5 2025.

Square Root, which opened in 2014 in the Lower Garden District, was even more ambitious. The only option was a multi-course tasting menu. It was the most expensive restaurant in New Orleans.