Your lid, made of glass.
Close your MacBook and the display lifts away as a pane of frosted glass. It moves at the speed of your hand. Stop, and it stops. Open it again and the whole thing retraces itself.
Pay once. Yours on up to 5 Macs. No account, no licence key.
What it does
A material. A small event, every time.
A pane of frosted glass, hinged along the bottom edge of your display and moved by your lid. The idea comes from the fold on iPhone Duo. The glass is modelled — it lifts, leans and catches the light — rather than painted over a screenshot.
01
Your lid moves it. Nothing else does.
The fold reads the lid-angle sensor directly. Move slowly and it moves slowly. Stop halfway and it holds there. Reverse, and it unfolds.
02
Clear where it touches. Frosted where it lifts.
The pane lifts off the display as it tilts. The gap is nothing at the hinge and grows toward the top, so the bottom of your screen stays almost untouched while the top frosts over.
03
Etched glass, not a blur.
Grain in the material. Lighting, Fresnel reflection and a specular sheen, all running off the real tilt. A sheet of glass catching the room — not a blur laid over a screenshot.
The app
See every change. Without closing a thing.
A live picture of the material sits beside the controls, with a scrubber that runs the fold by hand. Frost, Perspective and Edge softness shape the glass. Responsiveness and Hinge sensitivity decide how tightly it tracks. Play the fold to watch the whole thing, and Reset puts every setting back.
The details
Before you buy.
Worth reading properly. One specific dependency, and one rough edge. Both are better known in advance.
How it works
- Lid sensor
- Reads the hinge angle from the Mac's own sensor. The fold engages at 95° and is complete by 12°, and the same angle always means the same glass — so opening retraces closing exactly.
- Live display
- Your screen is captured and the glass is rendered over it with Metal, so windows and wallpaper move as one surface rather than as layers.
- Intensity
- Low, Medium and High, with Frost, Perspective and Edge softness on sliders underneath. Glass can match your system appearance, or stay light or dark.
- Feel
- Responsiveness sets how tightly the fold tracks your hand. Hinge sensitivity sets how much travel it spends per degree.
- Menu bar
- Sits quietly in the menu bar, with the live lid angle up there if you want it.
- At rest
- Nothing runs while the lid is still. No background work, and no cost to leaving it on.
Requirements
- macOS
- 14.0 Sonoma or later.
- Mac
- Any Mac with a built-in display. Apple silicon MacBooks get the full effect — they have the lid-angle sensor the animation is driven by.
- Intel MacBooks
- Work, but fall back to a timed animation on lid open and close rather than tracking the hinge continuously.
- Desktop Macs
- No lid, no effect.
- Permission
- Screen Recording, and it is not optional — the glass is built out of your live display, so there is nothing to render without it.
- Download
- Universal binary. 3.4 MB.
Private by design
- On your Mac
- The display is read to build the glass and those frames stay in memory. Nothing is written to disk, and nothing is sent anywhere.
- Only while moving
- Capture runs while the lid is in motion and stops the moment it settles.
- No network
- Mac Duo does not connect to the internet. No analytics, no accounts, nothing phoning home.
- No account
- Pay. Download the disk image. Drag it to Applications. Nothing to create, nothing to enter.
One rough edge
The first launch takes one extra step.
Mac Duo is not yet notarized by Apple, so the first time you open it macOS will say it cannot verify the app is free of malware. Nothing is wrong. Open System Settings → Privacy & Security, scroll down, and click Open Anyway. That is the whole workaround, you only do it once, and we would rather you heard it here than after paying.
Read the full install guideYour lid, made of glass.
£2.99, once. 3.4 MB. Yours the moment you have paid.
Up to 5 Macs · Refund on request
Questions
Questions, answered.
Why does it need Screen Recording?
The glass is built out of your live display, so without that permission there is nothing to render. Capture runs only while the lid is actually moving. Nothing is recorded, saved, or sent anywhere — Mac Duo does not connect to the internet at all.
macOS says it cannot verify the app. Is that normal?
Yes, and it is expected. This build is not notarized by Apple, so the first launch shows a warning. Open System Settings → Privacy & Security, scroll down, and click Open Anyway. You only do it once. The old Control-click trick no longer works on recent macOS versions.
Which Macs get the full effect?
Apple silicon MacBooks, because they carry the lid-angle sensor. Intel MacBooks run a timed version of the animation instead. Desktop Macs have no lid, so there is nothing to drive.
How many Macs can I use it on?
Up to five of your own. There is no licence key, no activation and no account — Mac Duo trusts you, and your download link is tied to your email if you need it again.
Is there a subscription?
No. One payment, and the app is yours. No accounts, no licence keys, no trial countdown.
What about updates?
If there is an update we will email you, and you can download it with the same email address you bought with. Automatic updates are planned for a later version.
Does it drain the battery?
It does nothing at all when the lid is not moving — no background work, no polling. While it is animating it takes about 1.5 ms a frame on an M3 at full resolution, with room to spare at 120 fps.
Can I get a refund?
Yes. If it does not do what you expected, email hello@studiogohl.co.uk and we will refund you. No form, no questions.