Amazon wowed the internet back in 2016 with its vision of a cashier-free store , Amazon Go, where you could just grab what you want and get an auto-tallied and auto-paid bill, courtesy of computer vision and other sensors that track what you take. After trialing its first store in Seattle with employees for more than a year, the long-delayed public opening finally came on January 22 this year.

Now we know it wasn’t a one-off effort: Today GeekWire reports that a second location is prepped for opening soon.

Following a reader tip, GeekWire reporters confirmed that Amazon is putting the finishing touches on a second store in the Madison Centre, a 36-story high-rise across from the Seattle Central Library. This one is much bigger–coming in at about 3,000 square feet, versus 1,800 square feet of the original location. More product and bigger crowds will further challenge Amazon’s cameras and algorithms–a necessary step if it’s going to scale. In May, Amazon confirmed plans to open Go stores in San Francisco and Chicago. Recode reports that at least six stores beyond Seattle are in the works. But it’s unclear how far Go will go, or even if Amazon knows.

Related: This AI Startup Wants To Automate Every Store Like Amazon Go

In 2016, Business Insider said it had unearthed Amazon documents showing plans to open about 2,000 automated stores–a report that Amazon quickly batted down. Amazon also says that it has no plans to expand the cashier-free technology to the Whole Foods supermarket chain, which it bought in August 2017. If it were to scale Go for a full-size store, the logistical challenge would grow considerably. The average Whole Foods store has 40,000 square feet of floor space.