No, not a memorial to US poet Frank O’Hara, as poetry lovers might imagine, or John O’Hara, for those who prefer prose. Two of three such devices, much-trodden-on, let into the sidewalk of Telegraph Avenue, Berkeley, California, long ago and discovered in December 2013 and photographed by John Tranter. Once upon a time the O’Hara Company made these little brass lids for under-sidewalk pipes — for fuel oil, perhaps — some ten centimeters square, about the size of a CD cover. The address of the firm in Los Angeles, some three hundred and fifty miles away, is now (in 2013) a near-derelict building not far from the Los Angeles Galvanizing Company.