Look up as you pass Ceintuurbaan 251: on the elaborately carved wooden gables of the 1884 neo-Gothic mansion here you'll see two cheeky lime-green goblin sculptures dressed in red hats and shorts; one is holding a red ball and the other is reaching to catch it. The building was designed by architect AC Boerma; it's thought the sculptures symbolise his client's surname, Van Ballegooijen, which translates in part to 'throwing a ball'. It's been a listed national monument since 1984.
Local legend has it that the ball changes between the goblins' hands at midnight on February 29 every leap year.