I saw the iPhones of the next decade in Apple's "liquid glass".

The lively opening ceremony of WWDC25 has come to an end. Although there is still no definite date for Apple Intelligence to enter the Chinese market, after more than two years of sluggish performance, Apple has finally brought us some relatively exciting news - a comprehensive visual overhaul of all its platform operating systems.

Different from the previous situation where iOS, macOS, watchOS, and visionOS each had their own style, this time Apple, under the unified version number "26", unexpectedly launched a design language that spans all hardware operating systems. From the Apple Watch on your wrist to the Apple TV that can fill an entire wall, they are all unified visually.

And this solution is Liquid Glass.

Digital Metamaterial

According to traditional design principles, it is usually difficult to unify the visual design language and interaction logic for hardware with huge size differences and completely different usage scenarios and methods. If forced to unify, it is inevitable to neglect one aspect while focusing on another.

In fact, Apple, which is always known for its design, has not been able to break away from this principle in the past. For example, the increasingly rounded style of iOS since version 11 didn't match well with the sharp and flat macOS at that time. It wasn't until the macOS Big Sur updated a wave of icons that the situation improved.

macOS High Sierra, released in the same year as iOS 11, still used irregular flat icons | hexnode

So, can Liquid Glass bring a turnaround to the current uneven situation?

According to the introduction video released by Apple on its Apple Developer account, Liquid Glass actually has a very deep origin - it is actually a reinterpretation of the popular and industry - pursued "Aqua" design language on Mac OS X 10.0 Cheetah twenty - five years ago.

Chan Karunamuni, an Apple human - machine interface designer, introduced Liquid Glass like this:

It is built based on our design experience with the Aqua user interface on Mac OS X, the real - time blur effect of iOS 7, the smooth animation of iPhone X, the flexibility of the Dynamic Island, and the immersive interface on visionOS. With this experience, instead of trying to reproduce real - world materials, we made Liquid Glass a digital metamaterial - it can dynamically refract and reflect light, and present natural dynamic effects like a liquid, reacting to touch and interface changes.

This is also a direction that many predictions before WWDC didn't cover: whether it was the design analysis "Physicality: The New Generation of UI Design" by former Apple designer and Halide camera founder Sebastiaan de With, or the concept maps made by various online experts, most only guessed that the new design would have a lot of "glass" attributes from visionOS, but didn't expect the "fluid" part.

Of course, from a hindsight perspective, the "Liquid" in Liquid Glass does have some clues: to adapt to more rounded screens, the non - through bottom bars widely used in iOS and iPadOS 26, and the fusion, splitting, and moving animations between components are exactly from the Dynamic Island that debuted in 2022 -

It is undoubted that the entire set of UI controls under the Liquid Glass specification has excellent animations. However, compared with background rendering, pre - baking, dispersion at the glass edges, and fluid animations, Liquid Glass has attracted our attention from another angle - its sense of deja vu.

If we use iOS 7 as a dividing line, you may clearly see that the overall design concept of iOS can be divided into three stages:

• From iPhone OS to iOS 6, the design was skeuomorphic.
• From iOS 7 to iOS 18, the design gradually became more flat with richer layers.
• And in iOS 26, it returns to skeuomorphism that "simulates physical characteristics".

This division seems reasonable, right? But unfortunately, it's wrong, because the iOS interface has always been a skeuomorphic design. This year's iOS 26 is not a "return to skeuomorphism" because even an extreme version like iOS 7 is also skeuomorphic. To understand this, we need to return to the definition of skeuomorphism itself.

The Skeuomorphism of iOS

As Apple itself promotes, Liquid Glass is essentially a "digital material" that combines the optical properties of glass and the fluid properties of a liquid. Although it only exists in a virtual environment, it mimics real - world physical objects. This kind of imitation is called skeuomorphism; and the product design that uses this principle is called skeuomorphic design.

Image | sketchplanations

From another perspective, skeuomorphic design is a design method that allows the design object to imitate real - world objects, borrowing their physical appearance, working principles, or behavioral characteristics, so that users can quickly get familiar with and accept the design object in a new environment. This concept may not be very intuitive to us today, but for users in the late 20th century who were used to controlling computers with command - line interfaces (CLI) when the graphical user interface (GUI) was just emerging, skeuomorphic design was undoubtedly revolutionary:

Image | XDA Forums

What's shown above is the absolute peak of skeuomorphic design - Microsoft Bob from 1995. It was a "simplified system" program running on Windows 3.1. Its principle is similar to third - party launchers on Android. Its main purpose was to make the originally rough and boring graphical interface of Windows more intuitive and user - friendly.

For example, in Bob, the document editor was really a typewriter, the calendar program was really a wall calendar, and you could only enter the mail by clicking on the mailbox, and so on. All operations were like "coming home", and users only needed to know how to operate the mouse to intuitively use Bob and find the corresponding functions by intuition, without having to understand why the web browser logo was a huge "e".

In contrast, the interface of Windows 3.1 was not very intuitive for users who were just getting in touch with GUI

But why can the seemingly very flat picture style of Bob also be called skeuomorphic design? Here, we must distinguish two concepts in skeuomorphic design: skeuomorphism in principle and skeuomorphism in style.

The aforementioned Sebastiaan de With wrote in his article predicting the design of iOS 26:

You've probably heard the term "skeuomorphism". But skeuomorphism doesn't just mean there are a lot of visual effects on the interface, like gradients, gloss, and shadows. Its real meaning is: to make it easier for users to transition from what they're used to (like a feature phone with a small plastic screen and rows of buttons) to the current form (phones are now screen - based and can display any buttons or interfaces you can imagine).

Simply put: skeuomorphic design doesn't only mean imitating real - world materials (like the texture of stones or the wrinkles of paper). The deeper meaning of skeuomorphic design lies in imitating behavioral patterns.

The most obvious example is the calculator in iOS: in the original iPhone OS in 2007, Jobs referred to the ET66 calculator of the German Braun company in terms of both material and layout to create the calculator app on the iPhone. For most users at that time who had only used feature phones and had never used a touch - screen, this similar color and layout could help them quickly understand and get started with the calculator app:

A design like the iPhone OS calculator is a skeuomorphic design. And more than a decade later in iOS 26, the buttons in the app still maintain a similar layout, just removing the reflection used to simulate buttons and the material used to simulate the LCD screen back then. Its usage method and operation logic are still "skeuomorphic" as they were more than a decade ago.

You may be curious: what kind of design is non - skeuomorphic? About twenty years ago, the Xelibri brand under Siemens gave an answer:

From left to right: Xelibri 4, Xelibri 2, Xelibri 6

As an experimental brand targeting the fashion market, Xelibri launched 8 mobile phones with different shapes in just one year, focusing on non - mainstream design.

But in 2000, there were many non - mainstream designs. Xelibri put the emphasis of non - mainstream on the keyboard: its layout scheme was neither the T9 keyboard of feature phones nor the dial of old - fashioned telephones, but a counter - intuitive concept design completely derived from science - fiction movies of the same era. This design method, which has no real - world reference and completely fails to establish an intuitive connection between the new interface and users' old habits, can be called "non - skeuomorphic".

Of course, Xelibri's result finally matched its unconventional design and outrageous price. It only sold about 780,000 units in the whole year of 2003, causing a huge loss to Siemens' main mobile phone business. It was shut down by its parent company just one year after its establishment to cut losses.

Another example is the "Game Space" on mobile phones, which is completely non - skeuomorphic because it has no real - world prototype

Back to Apple, iOS 26, which features Liquid Glass, is of course skeuomorphic, but so is iOS 18, and iOS 7 is also skeuomorphic in essence because it didn't try to make the calculator triangular, and the dial pad didn't rely on ninja - like hand gestures to select numbers.

The so - called "flat design" starting from iOS 7 is not the opposite of "skeuomorphism". More accurately, it is a "de - materialization" in visual style:

Image | The Verge

In a nutshell: the design theme from iOS 7 to iOS 18 should accurately be called de - materialization, rather than abandoning skeuomorphism, and what returns in iOS 26 is also skeuomorphism in terms of material. From beginning to end, iOS has always been "skeuomorphic".

iOS Vista

Although Apple's "Liquid Glass" is unique, glass is a common element in both three - dimensional and flat skeuomorphic designs and is not an original idea of Apple.

This is why since the release of the WWDC2