Support
Questions, problems or feedback: write to hello@duoworld.app. We usually reply within two working days.
How to see the depth
Choose how you look at the worlds in Settings, under Viewing, then View mode.
- Parallel stereo (the default): hold the phone at reading distance and look through the screen, as if at something far behind it. The two pictures drift together into a third one in the middle, and that one has depth.
- Cross-eye stereo: gently cross your eyes until the two pictures overlap into one in the middle, then let it come into focus.
- Standard 2D: a single picture, no technique needed.
- Wiggle: the picture switches between the two eye views, which shows depth without any technique.
- Red / cyan: wear red–cyan glasses, with red over your left eye.
The stereograms in the Static tab are single patterned pictures with a hidden shape. Look through the pattern as for parallel stereo, and the shape rises out of it. The first one can take a minute. To check what you are looking for, turn on Reveal shape in the viewer.
If your eyes feel tired or strained, or you get a headache or feel dizzy, stop and rest. Some people cannot see stereo depth; Standard 2D and Wiggle work for everyone.
Music
Music is off each time the app opens. Turn it on in Settings, under Music, where there are three original soundtracks and a volume control.
Saving and sharing
- Tap the heart on a world or stereogram to keep it in Favourites.
- Download PNG collections, in the Static tab, hands the stereograms to the share sheet as ZIP files of PNG images, for example to save them to Files.
Your data
There is no account. Everything you change stays on your iPhone, and deleting the app deletes it. Details: Privacy Policy.
Requirements
An iPhone with iOS 27.1 or later.
Terms
Use of Duo Worlds is governed by Apple's Standard End User License Agreement.