The Shape of Smartphones
How phones became black rectangles, and what comes next
- Human-Computer Interaction
Put the latest phones from Apple, Samsung and Google face down on a table, and you’ll have trouble telling them apart. Each one is a glass rectangle with rounded corners, made almost entirely of screen.
Twenty years ago, phones flipped, slid, swiveled, and some had full keyboards. In this post, I look at how phones became rectangles, why, and what I think the next shape will be.
Before the Rectangle
The first commercial handheld mobile phone, the Motorola DynaTAC 8000X (1983), weighed about 790 g, gave you 30 minutes of talk time and cost $3,995. Its display was a single row of red LED digits.
For the next 15 years, the goal was to make phones smaller. By 2000, the Nokia 3310 fit easily in a pocket.
But then the keypad and the screen had to compete for the same small surface, and manufacturers tried many ways to fit them together:
- Candy bars like the Nokia 3310 split the front between screen and keypad.
- Flip phones like the Motorola Razr V3 (2004) gave each its own half.
- Sliders like the Nokia N95 (2007) hid the keypad behind the screen until you needed it.
- Keyboard phones like the BlackBerry added a full QWERTY keyboard for email.
This was the most creative period in phone design, because nobody knew yet what a phone was mainly for.
A Giant Screen
In January 2007, Steve Jobs introduced the iPhone. He pointed out that smartphone keyboards are there “whether you need them or not,” with the same buttons for every app. His solution was to “get rid of all these buttons and just make a giant screen.”
With multi-touch, the keyboard became software that only appears when needed. A calculator could show number keys, a game a joystick, and a video the whole screen. Since the interface now lived in software, the hardware no longer needed a shape of its own. Within a few years, almost every smartphone was a rectangular slab.
Bigger, Taller, Thinner
Once the screen was the phone, the goal became fitting more screen into the same hand and pocket.
Bigger: The first iPhone had a 3.5-inch screen. In 2011, Samsung’s 5.3-inch Galaxy Note was mocked as a “phablet,” but it sold well, and Apple followed with the 5.5-inch iPhone 6 Plus in 2014. Browsing, videos, maps and photos all benefit from more space.
Taller: Width decides whether you can use a phone with one hand, and in a 2013 study of 1,333 people, Steven Hoober found that 49% did. So phones grew taller instead. In 2017, the LG G6 and Galaxy S8 moved from 16:9 to 18:9 and 18.5:9, showing more of the vertically scrolling content most apps use.
Thinner: In 2025, the iPhone Air (5.6 mm) and Galaxy S25 Edge (5.8 mm) competed for the thinnest phone. Ironically, their camera bumps stick out further than ever.
Looking back, the shape changed because input moved into software, phones became screens for content, and touchscreens and OLED made it technically possible, all within the fixed limits of hands and pockets. Form follows function: when the function is the screen, the form becomes a screen.
The Rectangle Hits a Wall
The rectangle has now run out of room. The screen covers the whole front, phones are as tall as hands allow, and thinner phones don’t add screen. The only way to fit a bigger screen into a pocket is to fold it.
The first foldables appeared in 2019, among them the Samsung Galaxy Fold, which opens like a book into a small tablet. Flip phones like the Galaxy Z Flip and Motorola Razr have since come back as foldables too.
Foldables are still a niche, at 2.5% of global smartphone shipments in Q3 2025 according to Counterpoint Research. They cost more, weigh more, break more easily, and the crease is still visible. But in September 2026, Apple announced its first foldable, the iPhone Duo, with a 7.6-inch inner screen, starting at $1,999.
What Comes Next?
Foldables Go Mainstream
In the short term, I think foldables will become standard for high-end phones. Large phones were a niche until the iPhone 6 Plus, and within a few years nearly every flagship had a large screen. The iPhone Duo could do the same for foldables, and higher volumes will make them cheaper, lighter and more durable.
The Screen Leaves the Phone
In the long term, I think the screen will move off the phone and onto our faces. It’s the same logic as before: the biggest screen in the smallest device. Every hinge adds weight and cost, but a virtual screen in smart glasses can be any size, and you never need to hold it.
The first steps are here. In 2025, Meta released its Ray-Ban Display glasses, which show messages, maps and translations in one lens and come with a wristband that detects small finger gestures from muscle signals. AI assistants also reduce how much we need a screen, since asking is often faster than tapping.
But the phone won’t disappear yet. People still want screens, and glasses can’t fit a phone’s computing power and battery.
So I expect the phone to become a hub first: it stays in the pocket and does the computing, while glasses show the content and a wristband or voice handles input. Its shape will matter less, because we’ll rarely take it out.
Whether this is good news depends on design. As I argued in my post on Mark Weiser’s ubiquitous computing, the smartphone already pulls our attention away from the world, and a display in front of our eyes could make that worse. It will only be progress if glasses stay quiet until we need them.
Conclusion
The shape of phones has followed the screen. They shrank, experimented with flips, sliders and keyboards, and became screens with a little hardware attached. Foldables are the last trick for growing the screen without growing the device.
Next, I expect screens to move to our faces and the phone into our pockets. The black rectangle won’t change its shape. We’ll just stop looking at it.
References
- Steve Jobs. 2007. iPhone introduction. Macworld Conference & Expo, San Francisco. YouTube
- Steven Hoober. 2013. How Do Users Really Hold Mobile Devices? UXmatters. uxmatters.com
- MacTech. 2025. Global foldable smartphone shipments grew 14% annually in the third quarter (Counterpoint Research data). mactech.com
- Apple. 2026. Apple unveils iPhone Duo. Apple Newsroom. apple.com
- MacRumors. 2025. Meta Launches AI Glasses. macrumors.com
- Mark Weiser. 1991. The Computer for the 21st Century. Scientific American 265(3), pp. 94-104. doi:10.1038/scientificamerican0991-94
Image Credits
- Motorola DynaTAC 8000X by Redrum0486, CC BY-SA 3.0
- Nokia 3310 by Michael Brandtner, public domain
- Motorola Razr V3 by Raimond Spekking, CC BY-SA 4.0
- Nokia N95 by Asim18, CC BY-SA 3.0
- BlackBerry Curve 8330 by Tkgd2007, CC BY-SA 3.0
