Not a wallpaper pack: a whole social app that redraws every window, button, menu and tab bar in the style of a Mac you remember, on your phone.
Zurbax is a Frutiger Aero social app, and its interface has window styles the way old desktops had themes. Pick one and everything changes: the shape of the windows, the buttons, the fields, the scrollbars, the tab bar, the wallpaper and the font. On an iPhone the Mac looks come first and one of them is on from the moment you sign up; the sign-up itself is a setup assistant with "Welcome" in a dozen languages over a starry aurora.
Aqua at its calmest: light grey windows with centred title bars, gel-blue default buttons that glow, capsule tabs, a blue selection bar, an aqua scrollbar, a glassy 3D dock. The wallpaper is a purple nebula full of stars. Font: Lucida Grande.
Mac OS 8's Platinum: pinstriped title bars, square grey windows with 3D bevels and black outlines, rounded-rectangle buttons, a purple-blue selection colour and a mottled blue desktop. Font: Charcoal.
Bright, translucent, rounded panes with a light dock that blurs what's behind it, vivid blue accents, and a wallpaper of a coast at dusk in orange, pink and violet with ridges of hills.
The same rounded chrome in its dark form: see-through dark panes and dock, light text, and ribbons of pink and violet light drifting over deep blue.
The newest look: clear glass capsules everywhere that bend the light of the wallpaper behind them, line icons, and soft colour with clear drops drifting by.
One UI Classic: big white cards, pill buttons, pastel wallpaper, easy on the thumb. TouchWiz: dark bars with sky-blue accents, glossy buttons and a rippling pond with dandelion seeds. Samsung phones get these first.
Retro 95: grey bevels, navy title bars, a teal desktop. Luna XP: blue title bars, beige windows, a green hill. Glass 7: smoky see-through frames and a glowing taskbar.
Frutiger Aero: real liquid glass, gel buttons and bubbles over a live city of glass towers. Modern: clean and flat, light or dark.
Open Zurbax, go to Settings → Appearance, and pick a window style. Your phone's own family is listed first. Each style brings its wallpaper and font; change either afterwards if you like. Your profile page can wear a different style for visitors, too.
On an iPhone, open zurbax.com in Safari and tap install for the full-screen app.