In 2008, German sculptor Fabian Brunsing created the Pay & Sit bench as a form of artistic protest against commercialized public spaces. In order to sit down, users have to insert 0.50 € into a coin slot; once the allotted time runs out small spikes rise from the seat's bottom, forcing users to move. Needless to say, Brunsing was flabbergasted when park officials in the Shandong Province were inspired by his installation and created their own version of (actual) pay-per-sit benches.
@ibid @CriticalCupcake That's messy and too much work. Battery powered saws all, done in minutes.