Personal computing has grown by leaps and bounds in power, accessibility, and social prominence since the introduction of the first successful consumer-grade computer in 1974. Despite the emergence of new form factors, input methods, and even entirely new interaction paradigms in smartphones, tablets, and VR/AR, traditional computers continue to rely on an interface metaphor birthed in the early days of the personal computing movement: the desktop.

Though undoubtedly robust, the windowed desktop is not without its weaknesses. Our computational demands have reached a point where we can have dozens on dozens of windows and even more tabs open at any given time, and traditional desktops require us to position, resize, and select these windows with a cursor. There are several solutions provided by modern operating systems to reduce the cognitive load and monotony associated with window management, but these tools do not solve the core problems of the modern desktop model.

This limitation grows even more problematic when we consider that window layouts represent not only spacial arrangements but also semantic and functional ones. Computer "multi-tasking" is, in many circumstances, a misnomer; when we multi-task (or, more accurately, multi-app), we are often less concerned with doing two things at once than we are with doing a complex task made up of multiple components, linked in a complex non-linear flow. As a result, managing windows on a very low-level as we do now can feel like we are fighting with our computers to get work done.

At the same time, multi-touch has emerged as one of the most promising and rapidly evolving input technologies of the past decade. Companies like Apple and Microsoft have explored building hybrid, touch-driven PCs to bring this technology to more conventional computing experiences. The Microsoft Surface, arguably the first mainstream hybrid computer, is functionally a traditional laptop with multi-touch provided as a secondary input method. In contrast, the iPad Pro, Apple's flagship iPad, is first and foremost a tablet that integrates input methods from conventional laptops.

Surface Pro 7, 2019.

iPad Pro, 2020.

These devices are distinguished not by their form factors—which are quite similar—but instead by their software and interfaces. The Surface runs Windows, a traditional desktop OS built around cursor input, while the iPad runs iPadOS, an evolution of an operating system built for touchscreens. Each product straddles the line between a traditional desktop and a tablet, and each falls short of merging the two.

Current interface metaphors function better with specific modes of input over others; the desktop was designed around keyboard and mouse use, and touch interfaces were designed around multi-touch. Building an interface for multi-modal input requires a wholly different interface paradigm, built from the ground up to take advantage of a wide range of mixed interaction styles. No product currently on the market has been able to make good on a genuinely multi-modal approach.

In 2018, I began to develop a new interface concept that would address the window management issues of the traditional desktop and serve as a unifying metaphor for interaction across devices in both the conventional and hybrid computing space. My objective was to produce a near-to-market concept that could readily take advantage of existing hardware and technology while introducing a more ambitious rethinking of the modern desktop. I call it Carousel.

Atop this base is the interaction layer, which establishes an intelligible relationship between Carousel's window managment infrastructure and the user. It is made up of two related components: Carousel's card UI and its input command system.

Carousel utilizes a card metaphor to represent windows and describe their behavior. Cards behave analogously to their real-life counterparts: they can be placed, rearranged, and stacked. These metaphorical actions are brought to life in Carousel through a consistent vocabulary of motion, designed to build a user's intuition through repeated exposure.

This card interface works in parallel with a command system designed to accept a wide range of input combinations. Commands consist of three elements: a primary modifier, a secondary modifier, and an exit key.

Primary modifiers declare the scope of action—that is, whether a command is being directed to Carousel (Control) or the active window (Command). Secondary modifiers distinguish commands with the same exit key, and exit keys complete a command.

All commands within Carousel are mapped consistently under this paradigm. They can be accessed using just a keyboard or in tandem with another input device, like a mouse, trackpad, or touchscreen.

Carousel's command system brings clarity to the often inconsistent structure of traditional desktop shortcuts by mirroring the hierarchy of on-screen information. This hierarchy also applies to multi-touch: three to four finger commands are used for window management, while one to two fingers execute in-app commands, like scrolling, zooming, and panning. This approach resolves much of the confusion with touch commands on devices like the iPad, which attempt to distinguish one command from another by factors that can be difficult to predict or engage reliably, such as with timing, velocity or touch zones.

The power of Carousel's window management approach is fully realized with the addition of its final component: workspace management. Like the layers before it, workspace management is designed to allow users to easily craft relationships between tools and bodies of information, but this time at a level above a single fullscreen view. You can view workspaces in context and by relationship—both through automated defaults and user-created connections.

Users can browse, group, pin, and merge workspaces in the management perspective. Workspaces can also be sent to a different display.

In this view, Carousel provides a summary of both your active workspaces as well as your workspace history. Because Carousel is tree-based, it can easily recreate past spaces on demand. This view also allows you to create groups: collections of individual workspaces dedicated to a larger and more complex task, project, or idea. Once created, you can summon and dismiss a group just like any workspace.

Done with a project for the day? Just close the group or workspace. Carousel will keep track of it in your history and recall it whenever you need it.

In a final level above groups, Carousel allows you to create contexts: a superset of groups and workspaces dedicated to a broad area of responsibility that can be assigned to a physical location using GPS or near-field data. A context has its own history and is designed to create a layer of high-level separation between various areas of your life.

If a user assigns a location and gives Carousel permission, a context can be automatically switched to when the device is brought to that specific location. You can maintain separate work and personal life contexts, for example, and have Carousel switch between them when it realizes you have moved to a different space. In this way, Carousel's digital relationships can map onto spatial relationships in the physical world.

To switch contexts manually, use the drop-down toggle at the top of the view. All context items remain discoverable via universal search.

This final layer combines with the previous three to create a flexible digital work environment that scales and shifts with your needs.