Cuba has two currencies and several economies.
Let's start at the bottom. There are no shops, or very few. In central Havana, on the ground floor, almost all the buildings are residential; often crumbling communal space with a few bits of furniture and a questionable staircase. If you want something, it's under the counter - not literally, there is no counter - round the back, cash in hand, nod and wink. I saw an old truck, one of many, but this one had a fresh spray of paint; a rather odd shade of royal blue. The whole scenario popped into my head straight away: Apparently someone's got hold of a consignment of this blue paint, someone else's wife's cousin has a spraygun, Garage Jesus has a compressor...bosh. Blue truck.
Maybe some money changed hands, in which case it would have been Local Pesos, as opposed to Pesos Convertibles. Both types are only available, and can only be exchanged, within Cuba. The Convertible - CUC - is the official currency which you get at the airport, bank or wherever and is roughly equivalent to a Euro; there are 25 Locals to 1 CUC, and they're only available from civilians. There must be a finite (and slowly decreasing) number in circulation, all solid notes and coins, but they're great for buying stuff from street traders like Biscuit Lady and Fruit Bloke - you get more biscuits and fruit.
Going up a rung, everyone's equal in Cuban society, right ? Um. Occasionally a brand new Audi, Merc or BMW would appear. Silver wagens that would be noticeable in London, but in a country where old Ladas are the norm they stood out like sore thumbs.
More to come...