A foldable display shaped like a Nintendo DS

Unfold a foldable and it can use its display as two. A Nintendo DS also has two screens. That shared shape is now used: on an unfolded display the upper screen is given room and the touch screen sits between the pad and the buttons, as it does on the machine itself.

The Galaxy Fold 8 arrived and the iPhone Duo was announced, and displays you unfold stopped being unusual. Unfolded, they divide the display in two and run two things at once. A Nintendo DS is also a machine with two screens, so the two shapes resemble each other.

Until now none of that resemblance was used, because the two screens were drawn joined into one picture. Joined, they make a tall picture, and an unfolded display has more width than height, so the height fills first. The picture stops with both sides left empty.

So on a display with room to spare the two screens come apart. Picture the machine itself: the pad is to the left of the lower screen and the buttons are to its right. They are placed the same way here. The touch screen moves down between the pad and the buttons, and the upper screen takes the whole width.

The touch screen stays close to the size of the real one. At the unfolded Fold 8 size it is 262 points, and the hardware screen is 256 pixels across. What a fingertip meets is matched to the machine, and the room left over goes to the upper screen — which becomes three times larger.

A phone is unchanged. Where the space between the pad and the buttons is too narrow to hold a touch screen, the two are drawn joined as before. If the old picture suits you on a wide display too, choose Stacked under screen arrangement in Settings.

This has not been checked on foldable hardware. It was measured and tuned against the Fold 8 and iPhone Duo display sizes in a simulator and an emulator.