At a glance, Ice Cream Sandwich seems similar to the Android of years past. You have five home screen panels that hold any combination of app shortcuts, folders and live functioning widgets. Each is made up of an invisible grid that, like previous phone-based versions of Android, can support as many as 16 shortcuts (four across and four down). But beneath that basic shell, ICS is a whole new game.
You can practically see the fresh paint everywhere you look in the system. Gone are the harsh green and black colors of yore, replaced now with a soft blue-and-gray-based scheme. System icons are more brilliant, with bright colors and three-dimensional textures. New transitions and animations are sprinkled throughout the OS, adding subtle but important layers of polish.
As for the home screen itself, Ice Cream Sandwich provides a new favorites tray that stays in place at the bottom of the screen as you swipe from one panel to another. The tray houses a permanent link to your app drawer along with four customizable icons; you can anchor any shortcut or folder into those spots by simply dragging and dropping it into place.
ICS also introduces a new persistent search box across the top of the home screen. Tapping the main part of the box brings up Android's universal search field, which simultaneously covers the Web and most content on your phone. Tapping the microphone at right end of the box, meanwhile, brings up Google's Voice Actions utility, which allows you to conduct a Web search, place a phone call, send a text or email, or get driving directions by speaking into your device.
(Don't tell Siri, but that's actually a function Android has had for more than a year.)
The button-free philosophy
Perhaps the most striking shift with Ice Cream Sandwich is its move away from the four physical buttons that have long been Android phones' most identifiable feature. In fact, the Galaxy Nexus -- the flagship Android 4.0 phone -- has no buttons on its face whatsoever.
Instead, you get a trio of virtual buttons at the bottom of the display: one to go back a step, one to return to your home screen, and one to multitask, or toggle among recently used applications. These buttons will be familiar to Android tablet users; they actually first appeared in Honeycomb, as did an early implementation of the button-free philosophy. But for Android phones, they mark a major shift.