Talking about monumental visual art in a picture-free medium means, as The New Yorker’s Adam Gopnik admits, that the odds of failure are quite high. How can you explain Cubism or its wonky, prismatic appeal without visual aids? But it seems to be the week for rule-breaking and Gopnik’s modest pre-emption is unnecessary. His Essay on Cubism, for Radio 3’s strand on Paris 1913, rubbishes perceived wisdom: it’s not supposed to be difficult “or a profound, philosophical exploration of time and space”. Picasso and Braque, the Lennon and McCartney of art, says Gopnik, were absurd. Their work was fun, a puzzle meant to be enjoyed as one that gave us art’s “first self-consciously cognitive style”. Which is the Gopnik way of saying that Cubism reminds us that we see primarily with our minds; the paintings can be abstract, but that doesn’t stop our brains from rearranging scrambled shapes and lines into something recognisable.Cubism touches us, he teases art historians, because it is a happy style and 1913, Gopnik dovetails, was the last happy European year.