Apps made for iPhone Duo

Two screens, one app

Closed, the iPhone Duo is a narrow phone with an outer screen of 466 × 678 points, made for one hand. Open, it becomes a wide inner screen of 951 × 669 points that folds down the middle like a book.

Unfolding doesn't relaunch an app. It resizes it, in the middle of whatever you were doing, so a well-built app keeps your place, your text and your scroll position when the phone opens or closes.

What a Duo app should do

• Finish something useful on the closed screen, not just show a preview.
• Use the open screen for a second level: a list beside its detail, a board beside its pieces. Not the same layout, only bigger.
• Keep everything you were doing when you unfold or fold it.
• Keep buttons, sliders and text fields off the fold in the middle of the inner screen.
• Look right half-open, standing like a tent or lying like a laptop.

How Goldfold uses the fold

Goldfold is a glass of water on the closed phone, with a goldfish inside. Tilt it and the water sloshes. Open the iPhone Duo and the glass tips over: the water pours across the fold and settles into an aquarium that fills both halves.

The fold is part of the play. In Fold jump, the fish leaps from one half to the other. In Fish hop duel, two people play at once, one on each half. Eggs wait for you to open the phone before they hatch.

And on any other iPhone

Goldfold also works on every iPhone with iOS 18 or later. There it stays a glass, with the same fish, the same care and all the single-player games.