“Do you know what a frog is?” Kimi Pu, 9, asks her dad with a grin, pointing at a fork. “Frog?” he repeats, sheepish but smiling. “Frog’ is an animal—this is a fork.” “Fork! Sorry!” he says. “Great ...

There’s a certain state of mind I call crossword brain: It’s both intuitive and counterintuitive, knowing when to turn away from the seemingly obvious solution, but also knowing when to trust your ...