If the zoom feature in accessibility settings is turned on, you need to do a three-finger quadruple-tap to toggle the screen curtain. If the zoom feature is disabled, then it's a three-finger triple-tap.
If you have a Bluetooth keyboard, you can also toggle the screen curtain by pressing Control-Option-Shift-S.
Comments
Tap three times with three
Tap three times with three fingers on the screen. Then screen curtain turns off.
It's four taps if zoom is enabled
If the zoom feature in accessibility settings is turned on, you need to do a three-finger quadruple-tap to toggle the screen curtain. If the zoom feature is disabled, then it's a three-finger triple-tap.
If you have a Bluetooth keyboard, you can also toggle the screen curtain by pressing Control-Option-Shift-S.