Inspiration
We wanted to build something that felt native to a foldable phone instead of taking a normal mobile game and stretching it across a larger display.
The iPhone Duo creates a new kind of social interaction. Two people can physically share one device while seeing different information depending on how the phone is folded, opened, or positioned.
That inspired Duo Arcade, a collection of multiplayer games designed around the physical shape of the iPhone Duo itself.
What it does
Duo Arcade is a multiplayer game hub for games where players should not always be able to see the same information.
Instead of passing a phone back and forth or covering the screen with your hand, the iPhone Duo becomes part of the rules.
Depending on the game and the physical state of the phone:
- one player can see private information while the other cannot
- folding can switch which player has control
- hinging can reveal temporary information or actions
- opening the device can create a shared play space
- changing the device pose can move the game between private and shared states
The goal is to make the Duo feel like a physical tabletop console built for two people.
Our arcade includes game concepts inspired by hidden-information and turn-based games, where the fold state determines what each player is allowed to see and do.
How we built it
We built Duo Arcade natively in Swift and SwiftUI using the new iPhone Duo APIs.
The app listens to the device's physical state and hinge changes, then maps those states into gameplay.
Instead of treating folding as a layout event, each game can interpret it as an input.
For example:
- unfolded can belong to Player 1
- folded can belong to Player 2
- hinged can expose a shared action or transition
- different device orientations can determine which side of the screen belongs to which player
We also designed the UI around Duo-specific safe areas and the physical orientation of the device so each player's controls and information remain readable from opposite sides of the phone.
Challenges we ran into
The biggest challenge was designing games around a device that physically changes shape.
Normal mobile games assume one flat screen, one orientation, and one player looking from one direction.
Duo Arcade had to account for:
- two players looking from different sides
- private versus shared information
- fold state changing during gameplay
- controls changing ownership between players
- safe areas changing depending on device pose
- keeping the interaction understandable without adding complicated instructions
We also had to build everything quickly enough that the physical interaction remained the focus instead of overbuilding individual games.
Accomplishments that we're proud of
We're most proud that the phone itself becomes part of the social interaction.
Instead of using the Duo simply as a larger display, Duo Arcade makes its physical states part of the rules.
The same device can act as:
- a private hand
- a shared board
- a hidden-information screen
- a turn switch
- a physical divider between players
That creates multiplayer interactions that are much more natural on a foldable device than on a traditional phone.
What we learned
We learned that foldable devices create interesting possibilities beyond responsive layouts.
A hinge can behave like a physical control.
A fold can define who owns the screen.
A partially open phone can create privacy.
A fully open phone can create a shared tabletop.
The most interesting part of building for iPhone Duo was not asking how existing games should resize, but asking what kinds of games become possible when the device itself can physically change the relationship between players.
What's next for Duo Arcade
We want to expand Duo Arcade with more games built specifically around hidden information, simultaneous play, and physical device states.
Future games could explore:
- secret roles
- bluffing
- drawing and guessing
- strategy games
- reaction games
- asymmetric multiplayer
- games where the hinge itself becomes a timer, reveal, or action
Our goal is to make Duo Arcade feel like a new category of portable social gaming built specifically for foldable devices.
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