When the original iPhone was released, it adopted a number of innovative features, one of its biggest being the software keyboard. Nowadays, you’d be hard-pressed to find a physical keyboard, proving just how popular the on-screen keyboard has become.

To celebrate the original iPhone’s launch, the man who created Apple’s software keyboard, Ken Kocienda, shared a photo of early iPhone prototypes. These served as the test subjects for Kocienda to perfect the keyboard that would eventually launch with the original iPhone.

The devices, known as Wallabies, were essentially big hunks of plastic with home buttons and 3.5-inch screens. Obviously, they didn’t exist to show off Apple’s famed design acumen. Rather, their touchscreens provided Kocienda with the perfect platform to develop the iPhone keyboard.

According to Kocienda, returning the prototypes to Apple after he left the company was “tough.” He adds, “Like saying goodbye to old friends.”

It’s a good thing Kocienda was able to develop such a great keyboard, otherwise the end product could have been very different. It’s cool to get a look behind-the-scenes at what these engineers used to make something all iPhone owners take for granted.

At the time, jumping from a physical keyboard to one that was entirely software was a major shift. Now, it’s crazy to think of the iPhone without anything other than a software keyboard.

Check out the prototypes Kocienda used in the photo above.