British library

I had a meeting in London, today, with a client who doesn't have a London office, so we met at the café in the British Library.

It was a lovely space in which to meet, with stacks of books behind us and the gentle bubbling of conversation all around us. At one point we had a break and as I stretched my legs I came across this.

It's clearly some kind of printing device but I couldn't suss out how it would work and there was no explanatory plaque. Sort it out British Library!