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I don't think it works on the default wallpaper; you need to use a photo as the wallpaper, and scaling/cropping it might help as there's that little extra bit of real estate.

It actually works better using Apple default wallpapers than other user wallpapers.
 
More so with the Apple dynamic wallpapers.

i agree i just realized if i used it its interactive and you tilt the phone the bubbles go down the direction you are tilting it towards. more interactive than android's phase beam which looks similar
 
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