"This has to be a render," is my first thought as I watch these robots moving quickly over a seemingly infinite grid of crates. I am wrong. "Because the robots are brand new, it looks like a render but in fact it's 100% real," answers Alex Voica, the head of technology PR and communications at Ocado, a British online-only supermarket that delivers orders to customers straight from its warehouses.

Ocado sells everything you can find in a brick-and-mortar supermarket–from meat, dairy, and produce to its own brand of home products, third-party goods, and even flowers, toys, and magazines. When it comes to online delivery, speed and efficiency are paramount, which is why the company has been working on automation since it was founded in 2000. While other companies rely on human workers to find and buy all of the items on an online customer's shopping list, Ocado is using a new kind of robot–or, more specifically, a swarm of them.