Sorting trash might be quite boring, and some people need some powerful incentive to do so. To inject more fun into the process of collecting empty bottles, Coca-Cola installed an arcade machine in Dhaka, Bangladesh. The Coca-Cola Happiness Arcade installation played games only if used plastic bottles were inserted.

There are 15 million people living in Dhaka, and this means that trash is actually one of the biggest problems of the city. Many of the people are not really concerned about recycling—they just don’t have a motivation to do so. Coca-Cola decided to inspire the recycling movement with a simple solution—the company installed machines, looking like vending kiosks—in 6 locations across the city.

Unlike traditional kiosks, the machines didn’t sell the bottles— instead, they were accepting the used packaging. To reward consumers for “donating” bottles, the kiosks played an arcade game.

The machine had just one game, a simple version of Pong, but it still helped collect thousands of empty plastic Coca-Cola bottles in just 6 days. The kiosk also invited consumers to play in pairs—the display read “grab a friend and start playing.”

“When don’t care about recycling, the environment is sure to head towards slow but sure disaster,” says Coke in the case study video.