Nice one! One of my Mum's engravings which she did when we lived in Montevideo 1958-1962 shows cars driving along the main road, La Rambla, beside the river Plate. One of them is unmistakably a bubble car, probably an Isetta. Jose Schneckenberger (in the Heinkel Trojan Club) says that the local bus company used a fleet of Isettas for carrying mail and spare parts.