Design student Fabian Brunsing has devised a fiendish device that makes pay toilets seem positively munificent: Dubbed “Pay & Sit: The Private Bench,” it consists of a bench covered with retractable metal spikes and a coin slot. If you want to sit down on the bench without an array of spikes jamming you in the keister, you’ve got to pay €0.50 (about 70 cents US).
As seen below, this causes the spikes to retract so you can sit on the bench, and also activates a timer. Shortly before the timer expires, you’re warned by a buzzer to get up; then, the spikes shoot back up. Beware!
Of course actual privatized benches, as you might find them in a shopping mall, do not usually embed this device.