This one is a copy of one made for the British Museum (who own the plans.) The Museum was seeking a donor who might fund construction of the printer part of the machine (they had already made the calculating part). So this U.S. philanthropist said, "I'll pay for the printer, but only if you also build me a whole Difference Engine for my collection." And they did! This is Difference Engine No. 2, on display for a year, until it goes into the philanthropist's own home.