From the real world to virtual to back again. It's strange to think that shopping carts have evolved from this…

…to this…

…to this.

That's Amazon's Dash Cart, the IRL shopping cart they're debuting at their new Amazon Fresh supermarket in Los Angeles today. Though the space is 35,000 square feet--about the size of your average Whole Foods--the Amazon Fresh joints (there will be more) will not focus on natural and organic groceries, but on lower-cost items.

In addition to cost, Amazon is hoping that convenience will be a large part of the Fresh supermarket's appeal. Thus the designers of the Dash Cart were tasked with providing the following functionality:

1. Customers are "recognized" by the specific Dash Cart they grab a they enter the store.

2. Customers can access their Alexa Shopping Lists via the cart.

3. Customers can scan coupons via the cart.

4. Customers can throw whatever they want in the cart, and the cart somehow tallies everything.

5. Customers can walk out of the store without stopping to check out.

The designers handled this by incorporating three things: An interactive touchscreen, a code scanner and a built-in scale. Here's how it all works.

1. Customers are "recognized" by the specific Dash Cart they grab as they enter the store.

First off, the customers entering the store (which is invitation-only, initially) have to be established Amazon customers and smartphone users that have the Amazon app. To get the cart to "recognize" them, a QR code pops up on the app when they enter the store, and they scan this code into the cart's built-in code reader. Now the cart's got access to your Amazon account and credit card info.

2. Customers can access their Alexa Shopping Lists via the cart.

When customers pull up their Alexa shopping list, which can be modified on the fly, each item's location in the store is given.

3. Customers can scan coupons via the cart.

Via the built-in scanner.

4. Customers can throw whatever they want in the cart, and the cart somehow tallies everything.

This part is left vague in Amazon's description: "The cart uses a combination of computer vision algorithms and sensor fusion to identify items you put in the cart," and it's not clear if the cameras and sensors are in the cart, on the shelves, or both working in concert. In any case, a beeping noise and a green light on the front of the cart provide feedback to the user to let them know an item has been successfully scanned. If an item is placed in the cart that has not properly been scanned, the light on the cart turns and remains orange until a successful re-scan is performed. This also presumably serves as an anti-shoplifting measure.

For items that need to be weighed, like produce, the customer must item the item's code (presumably listed on a sticker on the item) into the touchscreen. The item is then weighed, according to Amazon, but it's not clear where on the cart the scale is located. The weighed amount is displayed on the touchscreen for the user to confirm.

5. Customers can walk out of the store without stopping to check out.

There's a Dash Cart lane that sounds similar to an EZ-Pass lane that customers roll their cart through to exit. Sensors identify the cart and charge your card. The customer leaves the cart in the store and removes the groceries--which, from the get-go, have been placed in 1-2 of the customer's own bags inside the cart, not the cart itself--and exits the store.

The first Amazon Fresh supermarket opens today in L.A.'s Woodland Hills neighborhood. Initially invitation-only, Amazon says it will become open to the wider public within a matter of weeks.