It's election time in the Czech Republic, with parliamentary polls due to open this week.
Artist David Cerny has chosen to celebrate the occasion with a subtle artwork placed on the River Vltava.
The BBC's Rob Cameron says that the artwork appears to be a message to leftist President Milos Zeman and his supporters (the artwork faces the Prague Castle, seat of the president). However, Cerny is refusing to comment, saying the artwork speaks for itself.
In September, Cerny spoke to The Prague Post about Zeman, and his comments weren't positive. "Our president is just another reason not to live in the Czech Republic," he told the paper. "The political system here is not good, most people know that. I think I'd be happy to live in New York and not come back. I mean, I would come back, maybe for like three months in the year or something."
The Prague Post reports that Zeman is out of the country at the moment.