During the last century gondolas had become so garish that a new law was passed insisting that they must in future always be black, but you’ll still notice little personal touches like the coloured cushions, rugs or flower vases.
Gondolas used to be covered, either for shelter or for anonymity. The covering was made from a kind of oiled canvas called rasse which was exported to England in the 18th century and known as “Venetian”. It was used to bind the slats on blinds – hence Venetian blinds. (Oddly enough, you don’t often see Venetian blinds in Venice.)