Itty Bitty BMW

This morning as I was walking to work, I spotted the itty biity Pike Brewing Company car zipping down 5TH Ave amongst the modern day giant vehicles. I've only spied their BMW Isetta through the windows at the brewery in Post Alley. I figured the car moved, but never saw if leave it's roost. There were two men crammed into that interior. It looks like both men were of average height and build. They must have been shoe horned through the large single front door. Well, I've just discovered a picture of the little car. It actually has three doors and four wheels. No, wait. At closer inspection of the flicker images. It has two doors; the main large front door and there is one on the right side of the car that gains one enter to the back seat. I'm not too familiar with BMW's lineage. Therefore I don't know what model it is. Can someone please help with identifying the vehicle?