SodaStream already told Coca-Cola it wouldn’t stop using Coke bottles in its marketing. Now the company has set up its show across the street from Coke’s World of Coca-Cola museum in Atlanta. SodaStream, which sells do-it-yourself soft-drink machines, plans to erect a car-sized cage at Centennial Olympic Park filled with thousands of used soft-drink bottles and cans. The point: Buying packaged drinks clogs up landfills, while making soda at home helps save the planet. A similar display at a South African airport has drawn threats of a lawsuit by Coca-Cola, the world’s largest beverage maker. The upstart uses 30 such displays around the globe to take issue with the waste created by big soda companies.