From Gordon's link a couple of snippets that I rather liked:
Even positioning a company logo at the bottom of the bowl would work, although . . . companies probably would not want to encourage people to urinate on their trademark. The University of Louisville in Kentucky has been particularly inventive in this respect—placing the emblem of the rival University of Kentucky at the bottom of the urinal in some of their changing room
A Victorian urinal target dating back at least as far as the 1880s features a bee. The Latin for bee is apis, a vulgar joke understandable to Victorian gentlemen, but almost certainly lost on 21st-century men.