START WITH THE DEVICE
Meet iPhone Duo.
Two displays. A hinge. One continuous app. Get to know the space your interface can live in.
Learning
to adapt.
Choose a pose to watch the same interface adapt.
Conceptual browser model · illustrative dimensions · no Swift execution
{ }Make it real in Swift · Start with adaptive navigation
PUT THE MENTAL MODEL TO WORK
YOUR FIRST NATIVE SCREEN
Take the notes app into Xcode.
A small, complete SwiftUI project. Shared state, adaptive navigation, labeled system actions, and no fixed screen sizes.
Download the Xcode starter ↓- Open. Unzip and open
DuoNotes.xcodeprojin Xcode 27.1 or later. - Run. Choose an iPhone Duo simulator and press Run. Hardware needs your signing team.
- Try. Edit a note. Fold, unfold, rotate, and narrow the window. Check that the selection and draft survive.
Drafts stay in memory during the app session. Relaunching resets the sample. The included README has the source map and device-testing checklist.
Five experiments with a fragile implementation, live signals, and an event trace.
02 / APPLYAudit your first screen. ↗Run the scanner, improve real SwiftUI code, and verify the transitions.
03 / EXPLOREPlay with complete examples. ↗Interactive Mail, Notes, Media, and Layout demos in your browser.