At the heart of any watch is time; it is the core function of any timepiece. In the development of the all-new Apple Watch Series 4, previewed last week at the Steve Jobs Theatre on the Apple Park Campus in Cupertino, CA, and available tomorrow through Apple stores and Apple online, time remained front and center. This was doubled down by Alan Dye, Vice President of User Interface Design at Apple, whose design team reimagined what the "face" of an Apple Watch could provide. The Apple Watch Series 4 is being lauded for many new innovations, two important ones being the increase viewability of the watch face by 30%, while volumetrically making it smaller than past iterations. That accomplishment allowed for Dye and his team to think about complications in a whole new way.

By definition, complications are functional additions on traditional timepieces – second counters and timers come to mind. But Apple takes complications further on the new Apple Watch Series 4–allowing for a total of eight complications to simultaneously co-exist on the larger face. They can take the form of countless info-centric measurements like calendar reminders, Activity, UV indexes, and timers.

For developers working with Watch OS 5, the core operating system powering the Apple Watch Series 4, this means rethinking what can be shared on the "Home" screen of the Watch.  Complications are tappable throughout edge to edge screen that bodies the Watch Series 4. Tap into the very corner of the screen's infographics and it's responsive and actionable.

The addition of complications are not the only changes Apple made in Watch Series 4 face. Dye and his team also developed new fire, water, vapor and liquid metal metals, not through digital rendering, but by building out a studio to develop and capture the motions in real life. And while it would have been cheaper for Apple to render the faces, Dye tells us this is not a shortcut Apple would take. It may be above and beyond the means others would go, but make sense when one thinks about the considerations Apple put into not only the outward design of the Watch Series 4, but the user experience itself.

For an exclusive behind-the-scenes glance at how Apple makes their proprietary, animated Watch Series 4 faces, press play on the exclusive video below to get a never-before-seen look at the complicated process.

For those familiar with previous iterations of the Apple Watch, the Series 4 is the first major overhaul of the watch body itself. Beyond the already mentioned increased viewable face and size, Apple's design team has made other changes.

Apple Watch Series 4 features an all-new Digital Crown with haptic feedback. Dye tells adding haptic feedback to the crown enhances the user's feel for the device and where the a user's focus is positioned when working with the Watch. From my week of use, the haptic feedback helped me better understand where I was in position to a menu and especially when reading Messages. It's a minor addition with maximal impact on the user's side.

The addition of an electrical heart sensor with an electrode in the Digital Crown and electrodes on the back crystal provides users to utilized the ECG app to generate an electrocardiogram that monitors heart rhythms and "analyzes pulse rate data to identify episodes of irregular heart rhythms suggestive of atrial fibrillation" - both functions cleared by the FDA as sharable with your physician. Fall detection support is another health-centric addition found on the Apple Watch Series 4, and likely one that many will note when considering assistance devices for relatives and friends who may benefit from such features.

New yoga and hiking workouts have been added to the watch's workout program, in addition to advanced features for runners, including cadence and pace alerts. You can also participate in head-to-head competitions, monthly challenges, and personalized coaching, while sharing your activity with friends.

Lastly, the Apple Watch Series 4 is up to two times faster with 50 percent louder speakers, carrying an all-new S4 chip that is a complete Silicon in Package (SiP). The entire system is then fabricated onto one single component. The new Apple Watch is the only product in the world that runs completely on a SiP.

In addition to the iPhone XS, iPhone XS Max, and iPhone XR, the Apple Watch Series 4 rounds out all the offerings revealed last week in Cupertino. The Apple Watch Series 4 comes in silver, gold, and space grey, retailing for $399 with GPS and $499 with cellular network, available beginning September 21.

For more surrounding Apple's new products, we took photos on the iPhone XS. Here's how they turned out.

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