Adverts on vehicles are pretty inflexible. You usually get taxicabs or delivery vans with a giant sticker or even a full paintjob, in return for which the owners get some kind of regular payment.
Today’s invention is a more flexible way to get a mobile advertising message across.
I envisage panels of a vehicle’s bodywork each being equipped with an array of individual cooling contacts. These would locally cool the panel from inside the vehicle, forming a pattern in ice on the outside. This pattern could take the form of a high contrast, pixelated version of a famous logo, set in stark colour contrast to the normal colour of the unfrozen parts of the bodywork.
When a new sponsor was found, the pattern of cooling could be changed, by use of a computer interface in the vehicle, which would also allow selection of any required logos.