@philpem I recognise it, but can't remember the reference

@patterfloof it's the first couple of rows of keys on a Linotype machine. The big issue is if you mistype on a Linotype, you can't cancel the row of type - you have to fill the rack and let it cast the type bar, then ditch the bad one.
So if you ever saw "DCI Willows was reportedd etaoin shrdlu" in a newspaper back in the day - that's what happened.